Subjects -> BIOLOGY (Total: 3174 journals)
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BIOLOGY (1491 journals)            First | 1 2 3 4 5 6 7 8 | Last

Showing 401 - 600 of 1720 Journals sorted alphabetically
Cryoletters     Full-text available via subscription   (Followers: 4)
Cuadernos de Neuropsicología     Open Access   (Followers: 1)
Current Applied Science and Technology     Open Access  
Current Bioinformatics     Hybrid Journal   (Followers: 13)
Current Biology     Full-text available via subscription   (Followers: 235)
Current Genomics     Hybrid Journal   (Followers: 8)
Current Landscape Ecology Reports     Hybrid Journal   (Followers: 2)
Current Medical Science     Hybrid Journal   (Followers: 1)
Current Molecular Medicine     Hybrid Journal   (Followers: 2)
Current Opinion in Cell Biology     Hybrid Journal   (Followers: 51)
Current Opinion in Molecular Therapeutics     Full-text available via subscription   (Followers: 8)
Current Opinion in Neurobiology     Hybrid Journal   (Followers: 32)
Current Opinion in Structural Biology     Hybrid Journal   (Followers: 26)
Current Opinion in Systems Biology     Hybrid Journal   (Followers: 2)
Current Pharmacogenomics and Personalized Medicine     Hybrid Journal   (Followers: 3)
Current Protein and Peptide Science     Hybrid Journal   (Followers: 8)
Current Proteomics     Hybrid Journal   (Followers: 4)
Current Protocols in Bioinformatics     Hybrid Journal   (Followers: 1)
Current Protocols in Cell Biology     Hybrid Journal  
Current Protocols in Molecular Biology     Hybrid Journal  
Current Protocols in Mouse Biology     Hybrid Journal  
Current Protocols in Neuroscience     Hybrid Journal  
Current Protocols in Plant Biology     Hybrid Journal   (Followers: 2)
Current Protocols in Protein Science     Hybrid Journal   (Followers: 1)
Current Protocols in Stem Cell Biology     Hybrid Journal  
Current Research in Bacteriology     Open Access   (Followers: 3)
Current Research in Biostatistics     Open Access   (Followers: 8)
Current Research in Chemical Biology     Open Access  
Current Research in Neurobiology     Open Access  
Current Research in Parasitology & Vector-Borne Diseases     Open Access  
Current Research in Structural Biology     Open Access   (Followers: 2)
Current Research in Translational Medicine     Full-text available via subscription   (Followers: 1)
Current Research in Virological Science     Open Access   (Followers: 2)
Current Science     Open Access   (Followers: 117)
Current Stem Cell Reports     Hybrid Journal   (Followers: 4)
Current Stem Cell Research & Therapy     Hybrid Journal   (Followers: 8)
Current Topics in Developmental Biology     Full-text available via subscription   (Followers: 3)
Current Topics in Membranes     Full-text available via subscription   (Followers: 1)
Cytotechnology     Hybrid Journal   (Followers: 10)
Database : The Journal of Biological Databases and Curation     Open Access   (Followers: 10)
Dendrochronologia     Hybrid Journal   (Followers: 1)
Developing World Bioethics     Hybrid Journal   (Followers: 6)
Developmental & Comparative Immunology     Hybrid Journal   (Followers: 5)
Developmental Biology     Hybrid Journal   (Followers: 26)
Developmental Cell     Full-text available via subscription   (Followers: 46)
Developmental Dynamics     Hybrid Journal   (Followers: 4)
Developmental Neurobiology     Hybrid Journal   (Followers: 6)
Dhaka University Journal of Biological Sciences     Open Access  
Diatom Research     Hybrid Journal   (Followers: 3)
Differentiation     Hybrid Journal  
Digital Biomarkers     Open Access   (Followers: 1)
Disease Models and Mechanisms     Open Access   (Followers: 1)
Diseases of Aquatic Organisms     Hybrid Journal  
DNA and Cell Biology     Hybrid Journal   (Followers: 9)
DNA Repair     Hybrid Journal   (Followers: 3)
DNA Research     Open Access   (Followers: 4)
Doklady Physics     Hybrid Journal   (Followers: 1)
Drug Discovery Today: Technologies     Full-text available via subscription   (Followers: 12)
Drug Resistance Updates     Hybrid Journal   (Followers: 3)
e-Jurnal Rekayasa dan Teknologi Budidaya Perairan     Open Access  
Ecocycles     Open Access   (Followers: 4)
Ecohydrology & Hydrobiology     Full-text available via subscription   (Followers: 4)
Ecología en Bolivia     Open Access  
Ecological Engineering     Hybrid Journal   (Followers: 4)
Ecological Questions     Open Access   (Followers: 5)
Ecological Solutions and Evidence     Open Access  
Ecology and Society     Open Access   (Followers: 51)
Ecology Letters     Hybrid Journal   (Followers: 256)
Economics & Human Biology     Hybrid Journal   (Followers: 1)
Ecoprint : An International Journal of Ecology     Open Access   (Followers: 4)
Ecoscience     Hybrid Journal   (Followers: 2)
Ecosystem Health and Sustainability     Open Access   (Followers: 1)
Ecosystems and People     Open Access   (Followers: 4)
Educational Technology Research and Development     Partially Free   (Followers: 45)
EDUSAINS     Open Access  
EFB Bioeconomy Journal     Open Access  
Egyptian Journal of Basic and Applied Sciences     Open Access  
Egyptian Journal of Biology     Open Access  
Egyptian Journal of Natural History     Open Access   (Followers: 1)
EJNMMI Research     Open Access  
Ekologia     Open Access  
el-Hayah     Open Access  
Electromagnetic Biology and Medicine     Hybrid Journal  
eLife     Open Access   (Followers: 97)
Embo Molecular Medicine     Open Access   (Followers: 9)
EMBO reports     Full-text available via subscription   (Followers: 23)
Emotion Review     Hybrid Journal   (Followers: 20)
Endangered Species Research     Open Access   (Followers: 6)
Endocrine Connections     Open Access   (Followers: 4)
Endothelium: Journal of Endothelial Cell Research     Full-text available via subscription   (Followers: 4)
Engineering & Technology     Hybrid Journal   (Followers: 23)
Engineering Economist, The     Hybrid Journal   (Followers: 4)
Engineering in Life Sciences     Hybrid Journal   (Followers: 3)
Engineering Optimization     Hybrid Journal   (Followers: 19)
Ensaios e Ciência : Ciências Biológicas, Agrárias e da Saúde     Open Access  
Environmental Biology of Fishes     Hybrid Journal   (Followers: 4)
Environmental DNA     Open Access   (Followers: 1)
Environmental Dynamics and Global Climate Change     Open Access   (Followers: 22)
Environmental Epigenetics     Open Access   (Followers: 2)
Environmental Microbiology     Hybrid Journal   (Followers: 27)
Environmental Microbiome     Open Access  
Environmental Science & Technology     Hybrid Journal   (Followers: 196)
Enzyme and Microbial Technology     Hybrid Journal   (Followers: 12)
Enzyme Research     Open Access   (Followers: 4)
Epidemiology & Infection     Open Access   (Followers: 23)
Epigenomes     Open Access  
EPMA Journal     Open Access  
Ethiopian Journal of Biological Sciences     Open Access   (Followers: 3)
Ethnobiology and Conservation     Open Access   (Followers: 3)
Ethnobiology Letters     Open Access  
Ethnobotany Research & Applications : a journal of plants, people and applied research     Open Access   (Followers: 2)
Ethnoscientia : Brazilian Journal of Ethnobiology and Ethnoecology     Open Access  
Ethology     Hybrid Journal   (Followers: 11)
Ethology Ecology & Evolution     Hybrid Journal   (Followers: 17)
EuPA Open Proteomics     Open Access   (Followers: 2)
EUREKA : Life Sciences     Open Access  
European Journal of Biological Research     Open Access   (Followers: 1)
European Journal of Biology     Open Access   (Followers: 1)
European Journal of Cell Biology     Hybrid Journal   (Followers: 6)
European Journal of Ecology     Open Access   (Followers: 1)
European Journal of Neuroscience     Hybrid Journal   (Followers: 36)
European Journal of Obstetrics & Gynecology and Reproductive Biology     Hybrid Journal   (Followers: 18)
European Journal of Obstetrics & Gynecology and Reproductive Biology : X     Open Access  
European Journal of Phycology     Hybrid Journal   (Followers: 4)
European Journal of Protistology     Hybrid Journal   (Followers: 5)
European Journal of Soil Biology     Hybrid Journal   (Followers: 3)
European Online Journal of Natural and Social Sciences     Open Access   (Followers: 4)
European Scientific Journal     Open Access   (Followers: 1)
Evidência - Ciência e Biotecnologia - Interdisciplinar     Open Access  
EvoDevo     Open Access   (Followers: 4)
Evolution     Partially Free   (Followers: 143)
Evolution and Human Behavior     Hybrid Journal   (Followers: 23)
Evolution Letters     Open Access   (Followers: 8)
Evolutionary Applications     Open Access   (Followers: 6)
Evolutionary Bioinformatics     Open Access   (Followers: 12)
Evolutionary Biology     Hybrid Journal   (Followers: 25)
Evolutionary Computation     Hybrid Journal   (Followers: 11)
Evolutionary Systematics     Open Access   (Followers: 2)
EXCLI Journal : Experimental and Clinical Sciences     Open Access  
Experimental & Molecular Medicine     Open Access  
Experimental and Applied Acarology     Hybrid Journal   (Followers: 1)
Experimental Parasitology     Hybrid Journal   (Followers: 1)
Expert Opinion on Biological Therapy     Hybrid Journal   (Followers: 4)
Expert Opinion on Environmental Biology     Hybrid Journal  
Expert Review of Proteomics     Hybrid Journal   (Followers: 4)
ExRNA     Open Access  
Extreme Life, Biospeology & Astrobiology - International Journal of the Bioflux Society     Full-text available via subscription   (Followers: 5)
Extremophiles     Hybrid Journal   (Followers: 1)
F&S Science : Official journal of the American Society for Reproductive Medicine     Open Access  
Facta Universitatis, Series : Medicine and Biology     Open Access  
Familial Cancer     Hybrid Journal   (Followers: 2)
FASEB BioAdvances     Open Access  
Fauna Norvegica     Open Access  
Fauna of New Zealand     Open Access  
Febs Journal     Hybrid Journal   (Followers: 26)
Feddes Repertorium     Hybrid Journal  
Fems Yeast Research     Hybrid Journal   (Followers: 11)
FIGEMPA : Investigación y Desarrollo     Open Access   (Followers: 1)
Fire Ecology     Open Access   (Followers: 2)
Fish & Shellfish Immunology     Hybrid Journal   (Followers: 10)
Fish and Shellfish Immunology Reports     Open Access   (Followers: 1)
Fishes     Open Access  
Fitoterapia     Hybrid Journal   (Followers: 4)
Florea : Jurnal Biologi dan Pembelajarannya     Open Access  
Fly     Full-text available via subscription  
Folia Biologica     Free   (Followers: 1)
Folia Histochemica et Cytobiologica     Open Access  
Folia Microbiologica     Hybrid Journal   (Followers: 2)
Folia Primatologica     Full-text available via subscription   (Followers: 4)
Food and Bioproducts Processing     Hybrid Journal   (Followers: 3)
Food and Ecological Systems Modelling Journal     Open Access  
Food and Waterborne Parasitology     Open Access  
Food Webs     Hybrid Journal   (Followers: 1)
Forensic Genomics     Full-text available via subscription   (Followers: 7)
Forest Pathology     Hybrid Journal   (Followers: 1)
Forschung     Hybrid Journal   (Followers: 1)
Foundations of Physics     Hybrid Journal   (Followers: 41)
Free Radical Biology and Medicine     Hybrid Journal   (Followers: 6)
Free Radical Research     Hybrid Journal   (Followers: 2)
Freshwater Science     Full-text available via subscription   (Followers: 14)
Frontiers in Ecology and Evolution     Open Access   (Followers: 45)
Frontiers in Evolutionary Neuroscience     Open Access   (Followers: 7)
Frontiers in Life Science     Hybrid Journal   (Followers: 1)
Frontiers in Marine Science     Open Access   (Followers: 14)
Frontiers in Network Physiology     Open Access   (Followers: 2)
Frontiers in Neurogenesis     Open Access   (Followers: 2)
Frontiers in Neuroprosthetics     Open Access   (Followers: 6)
Frontiers of Biogeography     Open Access   (Followers: 4)
Frontiers of Biology     Hybrid Journal   (Followers: 2)
Frontiers of Environmental Science & Engineering     Hybrid Journal   (Followers: 3)
Frontiers of Medical and Biological Engineering     Hybrid Journal  
Functional & Integrative Genomics     Hybrid Journal   (Followers: 7)
Fundamental and Applied Limnology / Archiv für Hydrobiologie     Full-text available via subscription   (Followers: 3)
Fundamental Research     Open Access  
Fungal Biology     Hybrid Journal   (Followers: 6)
Fungal Biology and Biotechnology     Open Access   (Followers: 2)
Fungal Biology Reviews     Full-text available via subscription   (Followers: 9)
Fungal Diversity     Hybrid Journal   (Followers: 2)
Fungal Ecology     Hybrid Journal   (Followers: 6)
Fungal Genetics Reports     Open Access  

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Fishes
Number of Followers: 0  

  This is an Open Access Journal Open Access journal
ISSN (Online) 2410-3888
Published by MDPI Homepage  [84 journals]
  • Fishes, Vol. 7, Pages 142: Genetic Diversity Evaluation and Population
           Structure Analysis of Red Swamp Crayfish (Procambarus clarkii) from Lakes
           and Rice Fields by SSR Markers

    • Authors: Xin-Fen Guo, Min Liu, Yu-Lin Zhou, Wen-Yu Wei, Zhi Li, Li Zhou, Zhong-Wei Wang, Jian-Fang Gui
      First page: 142
      Abstract: The red swamp crayfish (Procambarus clarkii) is an important aquatic animal and has developed as a popular aquaculture species in China. In this study, a total of 72,839 SSR motifs were identified from transcriptional data, and 20 microsatellite markers of them were finally developed to assess the genetic diversities of seven wild populations from natural lakes and nine cultured populations from rice fields. Genetic diversity was slightly higher in the cultured populations than in the wild populations. The degree of genetic differentiation between cultured populations is slight, while a moderate to a large degree of genetic differentiation between wild populations and most of the variations occurred within individuals (79%). The analysis of cluster, principal coordinate analysis and STRUCTURE were similar, and they showed that isolation-by-distance pattern was not significant. The microsatellite markers developed in this study can not only be used for genetic monitoring of population but also provide important information for the management of breeding and cultured population in red swamp crayfish.
      Citation: Fishes
      PubDate: 2022-06-21
      DOI: 10.3390/fishes7040142
      Issue No: Vol. 7, No. 4 (2022)
       
  • Fishes, Vol. 7, Pages 143: Can the Life History Trait Divergence of Two
           Extremes of a Cold-Water Genus Distribution Offer Evidence for Their
           Vulnerability to Sea Warming'

    • Authors: Alba Serrat, Marta Muñoz
      First page: 143
      Abstract: Cold- and deep-water species such as Molva species show low resilience to anthropogenic pressures, and they become particularly vulnerable at the warm edges of their distribution. In this study, the poorly documented Mediterranean ling (Molva macrophthalma) population from the northwestern Mediterranean Sea was analysed. This area is considered a cul-de-sac in a sea-warming hotspot, where M. macrophthalma shows a low population health status and is experiencing a climate-related reduction in abundance. Several life-history traits (length at maturity, reproductive cycle, fecundity style, oocyte recruitment pattern, and breeding strategy) are here described for the first time to evaluate the reproductive performance (oocyte diameter and production) in relation to the fish condition status (the HSI and relative condition index). Additionally, the results are compared with those of a population of a similar species, the blue ling (Molva dypterygia), inhabiting the cool edge of its distribution, hypothesised to have a higher condition status. Our results indicate that M. macrophthalma is a capital breeder with restricted secondary growth recruitment and group-synchronous oocyte development. In relative terms, the stressed southern M. macrophthalma exhibited a worse condition, a lower investment in reproduction, a smaller size at maturity, larger but fewer primary growth oocytes, and a smaller size-standardized production of secondary growth oocytes than the northern M. dypterygia. Significant differences in the secondary growth oocyte recruitment were also found. These findings reinforce the environment’s role in shaping the reproductive potential and condition status. Altogether, this study suggests high sensitivity to anthropogenic pressures for both species, and, especially for Mediterranean ling, it shows the importance of introducing monitoring and conservation measures to ensure the sustainability of its populations.
      Citation: Fishes
      PubDate: 2022-06-21
      DOI: 10.3390/fishes7040143
      Issue No: Vol. 7, No. 4 (2022)
       
  • Fishes, Vol. 7, Pages 144: The Impact of Multiple Pond Conditions on the
           Performance of Dike-Pond Extraction

    • Authors: Jinhao Zhou, Wu Zhou, Qiqi Zhou, Yuanhui Zhu, Fei Xie, Shen Liang, Yueming Hu
      First page: 144
      Abstract: Dike-ponds in fisheries often present multiple pond conditions such as pure, suspended sediment, water bloom, semidry conditions, etc. However, the impact of these conditions on the performance of extracting dike-pond from remote sensing images has not been studied. To solve this problem, we explore the existence of such impacts by comparing the performance of four rule-based methods in two groups of test regions. The first group has few multiple pond conditions, while the second has more. The results show that various measure values deteriorate as the proportion of multiple pond conditions in the regions increases. All four methods performed worse in the second group than the first, where the overall accuracy decreased by 8.80%, misclassification error increased by 3.69%, omission error raised by 10.53%, and correct quantity rate dropped by 8.23%, respectively. The extraction method that ingested multiple pond conditions performed indistinguishably from the other methods in the first group. However, it outperformed the other methods in the second group, with a 4.22% improvement in overall accuracy, a 10.25% decrease in misclassification error, and a 19.03% increase in the correct quantity rate. These findings suggest that multiple pond conditions can negatively impact the extraction performance and should be considered in dike-pond applications that require a precise pond size, number, and shape.
      Citation: Fishes
      PubDate: 2022-06-22
      DOI: 10.3390/fishes7040144
      Issue No: Vol. 7, No. 4 (2022)
       
  • Fishes, Vol. 7, Pages 145: First Look into the Use of Fish Scales as a
           Medium for Multi-Hormone Stress Analyses

    • Authors: Emily K. C. Kennedy, David M. Janz
      First page: 145
      Abstract: Recent efforts have provided convincing evidence for the use of fish scale cortisol concentration in the assessment of long-term stress in fishes. However, cortisol alone is not sufficient to fully describe this state of long-term stress. Dehydroepiandrosterone (DHEA) is an androgen with actions that oppose those of cortisol. The means by which DHEA negates the effects of cortisol occurs in part via changes in the metabolism of cortisol to cortisone. The quantitation of cortisol, DHEA and cortisone could therefore provide a more comprehensive assessment of the overall status of physiological stress. As DHEA and cortisone have yet to be quantified within the fish scale, our first objective was to ensure our sample processing protocol for cortisol was applicable to cortisone and DHEA. Following this, we induced a state of long-term stress in goldfish (Carassius auratus). Some degree of elevation in all hormones was observed in the stressed fish scales. Additionally, cortisol and cortisone were significantly elevated in the stressed fish serum in comparison to controls while DHEA was undetectable in either group. Overall, these results suggest that fish scales provide an appropriate medium for the assessment of long-term stress in fishes via the quantitation of relevant steroid hormones.
      Citation: Fishes
      PubDate: 2022-06-23
      DOI: 10.3390/fishes7040145
      Issue No: Vol. 7, No. 4 (2022)
       
  • Fishes, Vol. 7, Pages 146: An Overview of Interlocation Sexual Shape
           Dimorphism in Caquetaia kraussi (Perciformes: Cichlidae) A Geometric
           Morphometric Approach

    • Authors: Jordan Hernandez, Amado Villalobos-Leiva, Adriana Bermúdez, Daniela Ahumada-Cabarcas, Manuel J. Suazo, Hugo A. Benítez
      First page: 146
      Abstract: C. kraussii is an endemic fish species from Colombia and Venezuela and represents a valuable food resource for local human communities. Due to its economic importance, the management and captive breeding of this species are of special interest. However, the anatomical similarities between sexes have been a problem for visual identification. It is also important to indicate that C. kraussii has cryptic morphological behavior between sexes, a topic that has been one of the main problems for the implementation of management plans. The following research studied individuals from three different localities along the Canal del Dique, Bolívar Department in Colombia, in which the body shape of C. kraussii was analyzed using geometric morphometric analysis. The analyses detected the presence of intralocality sexual dimorphism in two of the three localities analyzed, showing a low morphological variability among males, presenting conserved body shape, as well as a greater morphological disparity among females. This sexual shape dimorphism may be associated with the environmental variation among different locations. These results suggest the presence of two evolutionary forces acting asymmetrically between the sexes of C. kraussii, with males mostly subject to sexual selection pressure, while females are mainly subject to environmental pressures.
      Citation: Fishes
      PubDate: 2022-06-23
      DOI: 10.3390/fishes7040146
      Issue No: Vol. 7, No. 4 (2022)
       
  • Fishes, Vol. 7, Pages 147: Revealing Population Connectivity of the
           Estuarine Tapertail Anchovy Coilia nasus in the Changjiang River Estuary
           and Its Adjacent Waters Using Otolith Microchemistry

    • Authors: Tao Jiang, Hongbo Liu, Yuhai Hu, Xiubao Chen, Jian Yang
      First page: 147
      Abstract: The estuarine tapertail anchovy, Coilia nasus, is a migratory fish with high economic value in China. We collected fish from the Changjiang River (the Yangtze River) estuary, the Qiantang River estuary, and the southern Yellow Sea, and studied their relationships using otolith elemental and stable isotopic microchemistry signatures to assess the population connectivity of C. nasus. Results show that, in addition to Ca, other elements were present in the otolith core. The δ18O, Na/Ca, Fe/Ca, and Cu/Ca values of the Qiantang population were significantly higher than those of the others, whereas its δ13C and Ba/Ca values were found to be significantly lower. Otolith multi-element composition and stable isotope ratios differed significantly between the Qiantang and Changjiang estuary groups (p < 0.05); however, no difference was observed between the latter and the Yellow Sea group. Cluster analysis, linear discriminant analysis, and a self-organizing map strongly suggest possible connectivity between the fish populations of the Changjiang estuary and Yellow Sea, while the population of the Qiantang River estuary appears to be independent. Notably, results suggest a much closer connectivity between the fish populations of the Changjiang River and the Yellow Sea.
      Citation: Fishes
      PubDate: 2022-06-23
      DOI: 10.3390/fishes7040147
      Issue No: Vol. 7, No. 4 (2022)
       
  • Fishes, Vol. 7, Pages 148: Diel Vertical Habitat Use Observations of a
           

    • Authors: Taylor Anderson, Emily N. Meese, James Marcus Drymon, Gregory W. Stunz, Brett Falterman, Elias Menjivar, R. J. David Wells
      First page: 148
      Abstract: Understanding habitat use of elasmobranchs in pelagic environments is complicated due to the mobility of these large animals and their ability to move great distances in a three-dimensional environment. The Gulf of Mexico is a region where many highly migratory pelagic shark species occur, while in close proximity to coastal, anthropogenic activity including recreational and commercial fisheries. This study provides summary information on the vertical habitat use for a single male scalloped hammerhead and a single male bigeye thresher that were each caught and tagged with an archiving satellite tag. The scalloped hammerhead occupied shallow depths (<100 m) over the continental shelf during the 90 d deployment. The bigeye thresher exhibited strong patterns of diel vertical migrations by occupying depths below the thermocline (>350 m) during the day, then occupying shallower depths (50–100 m) during the night. By providing summary information, this note urges future research to provide scientific information on pelagic, highly migratory species for management efforts in the Gulf of Mexico region.
      Citation: Fishes
      PubDate: 2022-06-24
      DOI: 10.3390/fishes7040148
      Issue No: Vol. 7, No. 4 (2022)
       
  • Fishes, Vol. 7, Pages 149: Effect of Siberian Ginseng Water Extract as a
           Dietary Additive on Growth Performance, Blood Biochemical Indexes, Lipid
           Metabolism, and Expression of PPARs Pathway-Related Genes in Genetically
           Improved Farmed Tilapia (Oreochromis niloticus)

    • Authors: Mingxiao Li, Jun Qiang, Xiaowen Zhu, Jingwen Bao, Yifan Tao, Haojun Zhu
      First page: 149
      Abstract: Overnutrition in high-density aquaculture can negatively affect the health of farmed fish. The Chinese herbal medicine Siberian ginseng (Acanthopanax senticosus, AS) can promote animal growth and immunity, and regulate lipid metabolism. Therefore, we conducted an 8-week experiment, in which Oreochromis niloticus was fed with a diet supplemented with different concentrations of AS water extract (ASW) (0‰, 0.1‰, 0.2‰, 0.4‰, 0.8‰, and 1.6‰). The ASW improved the growth performance and increased the specific growth rate (SGR). Linear regression analysis based on the SGR estimated that the optimal ASW amount was 0.74‰. Dietary supplementation with 0.4–0.8‰ ASW reduced the triglyceride and total cholesterol levels in the serum and liver, and regulated lipid transport by increasing the high-density lipoprotein cholesterol concentration and lowering the low-density lipoprotein cholesterol concentration. Dietary supplementation with ASW increased the activities of superoxide dismutase and catalase in the liver, thereby improving the antioxidant capacity. Moreover, ASW modulated the transcription of genes in the peroxisome proliferator-activated receptor signaling pathway in the liver (upregulation of PPARα, APOA1b, and FABP10a and downregulation of PPARγ), thereby regulating fatty acid synthesis and metabolism and slowing fat deposition. These results showed that 0.4–0.8‰ ASW can slow fat deposition and protected the liver from cell damage and abnormal lipid metabolism.
      Citation: Fishes
      PubDate: 2022-06-24
      DOI: 10.3390/fishes7040149
      Issue No: Vol. 7, No. 4 (2022)
       
  • Fishes, Vol. 7, Pages 150: Unauthorized Stocking of an Endangered
           Bitterling Acheilognathus typus in an Irrigation Pond Detected and
           Substantiated by Biological and Human Lines of Evidence

    • Authors: Kenji Saitoh, Nobuo Inoue, Masatomo Hasegawa
      First page: 150
      Abstract: Acheilognathus typus, an endangered bitterling, was captured in an irrigation pond in the northern part of Niigata prefecture, Japan, in 2019. This bitterling species had once occupied that region. Its absence for years indicated the possible extinction of the bitterling there. We expected that the recently captured individuals are an unknown remnant stock of that endangered species found through an extensive survey. Mitochondrial genotyping, however, revealed that the recently captured individuals had a common haplotype with those from Kashimadai, Miyagi prefecture, Japan. The uniqueness of the haplotype to these two ponds indicates a stock identity between them. In the pond in Kashimadai, the illegal activity of catching the bitterlings by a person from the northern Niigata prefecture was detected in 2015. We conclude that the bitterling from the northern Niigata prefecture was stocked from a pond in Kashimadai. Our report is the first example of unauthorized bitterling stocking substantiated from both biological and human lines of evidence.
      Citation: Fishes
      PubDate: 2022-06-25
      DOI: 10.3390/fishes7040150
      Issue No: Vol. 7, No. 4 (2022)
       
  • Fishes, Vol. 7, Pages 151: Investment Feasibility Analysis of Large
           Submersible Cage Culture in Taiwan: A Case Study of Snubnose Pompano
           (Trachinotus anak) and Cobia (Rachycentron canadum)

    • Authors: Hsun-Yu Lan, Farok Afero, Cheng-Ting Huang, Bo-Ying Chen, Po-Lin Huang, Yen-Lung Hou
      First page: 151
      Abstract: Onshore farming for premium aquaculture is under scrutiny and criticism partially due to possible causes of adverse environmental impacts on other resource users and the surrounding environment. The best alternative to preventing or minimizing these impacts is to utilize open seawater by large submersible cage culture. The current operation in Taiwan has demonstrated that the culture operation is technically feasible but economically demanding because of high capital and operating costs. Therefore, this study conducted an economic analysis of the expansion of large submersible cage culture by selecting two premium species of snubnose pompano (Trachinotus anak) and cobia (Rachycentron canadum) and examined the profitability of large submersible cage culture investment. This study found that the current operation of four-unit cages highlighted a negative net present value and internal rate of return with a payback period of over ten and six years, respectively. Large submersible cage culture can be financially profitable when its operation unit expands from 8 to 24 units. Increasing unit cages to eight incurred a gross margin of 17.09%, BCR 1.21, with a payback period of 5.36 years. Expanding the operation to 24-unit cages was a potentially lucrative investment with a gross margin of 18.51%, BCR 1.23, PI 2.15, internal rate of return of 20.84%, and a payback period of 3.55 years. Sensitivity analyses revealed that market price and survival rate significantly impact the profitability of large submersible cage culture. Finally, it is suggested that producers could invest in 8-unit cages and maintaining the survival rate of snubnose pompano and cobia at 80% and 40%, respectively.
      Citation: Fishes
      PubDate: 2022-06-25
      DOI: 10.3390/fishes7040151
      Issue No: Vol. 7, No. 4 (2022)
       
  • Fishes, Vol. 7, Pages 152: Comparative Transcriptome Analysis of
           Differentially Expressed Genes in the Testis and Ovary of Sea Urchin
           (Strongylocentrotus intermedius)

    • Authors: Panpan Gou, Zhicheng Wang, Jin Yang, Xiuli Wang, Xuemei Qiu
      First page: 152
      Abstract: The quality of sea urchin gonad is important to consumers with high standards for nutrition and taste. However, few studies have been conductedon the molecular mechanisms that determine the quality of male and female sea urchins. In this study, our goal was to understand the differences and characteristics of gonad quality between sea urchin (Strongylocentrotus intermedius) males and females. The transcriptomes of males and females were obtained, with totals of 43,797,146 and 56,222,782 raw reads, respectively, comprising 128,979 transcripts and 85,745 unigenes. After comparative transcriptome analysis, a total of 6736 differentially expressed genes (DEGs) between the males and females were identified, of which 2950 genes were up-regulated and 3786 genes were down-regulated in males. We compared the expression of twelve DEGs with significant differences their expression levels and functional annotations to confirm the reliability of the RNA-Seq data. Five DEGs related to gonadal quality were found through enrichment analysis of KEGG pathways: 17β-HSD8, PGDH, FAXDC2, C4MO, and PNPLA7. Our study analyzes genes related to the taste and flavor of sea urchin gonads among the sexes and provides reference sequences and fundamental information concerning the nutrition and taste of S. intermedius gonads.
      Citation: Fishes
      PubDate: 2022-06-26
      DOI: 10.3390/fishes7040152
      Issue No: Vol. 7, No. 4 (2022)
       
  • Fishes, Vol. 7, Pages 153: Do Two Different Approaches to the Season in
           Modeling Affect the Predicted Distribution of Fish' A Case Study for
           Decapterus maruadsi in the Offshore Waters of Southern Zhejiang, China

    • Authors: Wen Ma, Chunxia Gao, Song Qin, Jin Ma, Jing Zhao
      First page: 153
      Abstract: The relationships between environmental factors and fish density are closely related, and species distribution models (SDMs) have been widely used in exploring these relationships and predicting the spatial distribution of fishery resources. When exploring the prediction of the spatial distribution of species in different seasons, the method of choosing the appropriate approach to the season will help to improve the predictive performance of the model. Based on data collected from 2015 to 2020 during a survey off southern Zhejiang, the Tweedie-GAM was used to establish the relationship between the density of Decapterus maruadsi and environmental factors at different modeling approaches. The results showed that water temperature, salinity and depth were the main factors influencing D. maruadsi, and they operated through different mechanisms and even resulted in opposite trends of density in different seasons. Spatially, the two modeling approaches also differed in predicting the spatial distribution of D. maruadsi, with the seasonal model showing a higher density trend in inshore waters than in offshore waters in spring but showing the opposite trend in summer and autumn, which was more consistent with the actual spatial distribution of the resource. By analyzing the effects of two different approaches on the prediction of fishery resources, this study aims to provide research ideas and references for improving the predictive performance of SDMs.
      Citation: Fishes
      PubDate: 2022-06-27
      DOI: 10.3390/fishes7040153
      Issue No: Vol. 7, No. 4 (2022)
       
  • Fishes, Vol. 7, Pages 154: Potential Role of Gastrointestinal Microbiota
           in Growth Regulation of Yellowtail Kingfish Seriola lalandi in Different
           Stocking Densities

    • Authors: Yan Jiang, Chaoyong Yu, Yongjiang Xu, Xuezhou Liu, Aijun Cui, Bin Wang, Heting Zhou
      First page: 154
      Abstract: A 90-day study was performed under three different stocking densities, including high density (10,000 fishes/cage), medium density (8000 fishes/cage), and low density (6000 fishes/cage), in a deep-sea net cage for yellowtail kingfish (Seriola lalandi). The physiological characteristics and growth performance were tested, and structural characteristics of the gastrointestinal microbiota were systematically analyzed. The results show that fishes with high density had a lower weight gain rate and a specific growth rate, as well as higher serum cortisol content. The diversity, types and numbers of dominant microbiota with significant differences, and the numbers of shared genera among the different groups all changed. Core genera in the gastrointestinal tract were obtained according to the principles of dominance, commonality, and difference. The changes in the relative abundance of the core genera might be related to the growth and physiological characteristics of the host. The ratio of Firmicutes to Bacteroidetes in the stomach and pyloric caecum, which favors the accumulation of energy by the host from the diet, was higher in the medium-density group than in the other groups. This indicates that the higher density could cause physiological stress and affect growth performance. In order to reduce the resulting growth differences, gastrointestinal microbiota might assist the host in accumulating energy, participating in the energy distribution by adjusting its structure. Based on the growth, physiology, and production practices, the medium density was the appropriate density in this study. This study provides a reference for the improvement of deep-sea culture technology and the promotion of healthy growth through the gastrointestinal microecological regulation of yellowtail kingfish.
      Citation: Fishes
      PubDate: 2022-06-28
      DOI: 10.3390/fishes7040154
      Issue No: Vol. 7, No. 4 (2022)
       
  • Fishes, Vol. 7, Pages 155: Unravelling Stock Spatial Structure of
           Silverside Odontesthes argentinensis (Valenciennes, 1835) from the North
           Argentinian Coast by Otoliths Shape Analysis

    • Authors: Santiago Morawicki, Patricio J. Solimano, Alejandra V. Volpedo
      First page: 155
      Abstract: The marine silverside (Odontesthes argentinensis) is an euryhaline species, distributed along the southwest coast of the Atlantic Ocean, present in estuaries, brackish coastal lagoons and shallow marine waters. It is a significant economic resource for local fisheries in southern Brazil, Uruguay and Argentina. The aim of this work was to contribute to knowledge on the stock spatial structure of the silverside, using otolith shape analysis, based on samples from nine locations in the Argentinian Sea, covering a large distribution range of the species. A combination of elliptic Fourier descriptors, Wavelet coefficients and otolith Shape indices were explored by multivariate statistical methods. The application of wavelet and combined wavelet, Fourier and Shape Indices were the most effective variables to discriminate between sampling sites (7.42 total error). PERMANOVA analysis of otolith shape revealed multivariate significant differences between north versus south locations (p < 0.0001). The results obtained show that the spatial structure of O. argentinensis presents a North–South gradient with marked differences between the extreme localities of the north (Mar del Plata, Quequén) with more elliptical shapes than those in the south (San Blas, San Antonio Este) and an isolated group conformed by Puerto Lobos.
      Citation: Fishes
      PubDate: 2022-06-29
      DOI: 10.3390/fishes7040155
      Issue No: Vol. 7, No. 4 (2022)
       
  • Fishes, Vol. 7, Pages 156: Potential Impact of Climate Change on Fish
           Reproductive Phenology: A Case Study in Gonochoric and Hermaphrodite
           Commercially Important Species from the Southern Gulf of Mexico

    • Authors: Thierry Brulé, Ximena Renán, Teresa Colás-Marrufo
      First page: 156
      Abstract: In tropical regions, temperature is the fundamental environmental factor controlling the reproduction-related physiological activities of fish. Tropical fish are particularly sensitive to climate change since they develop in a relatively stable thermal environment. A review was done to assess the potential effect of temperature rise on reproduction and population structure in the commercially important hermaphrodite grouper and wrasse species, and in gonochoric snapper species in the southern Gulf of Mexico. Temperature increase can disturb the aromatase synthesis and/or activity, which can affect the reproductive cycle and sexual differentiation in all studied species and the sexual inversion process in sequential hermaphrodites. Moreover, a mistiming or discontinuity in spawning seasonality could occur, with an alteration in the sex ratio in favor of males and a consequent reduction in populations’ fecundity. Furthermore, if the level of fishing exploitation enhances species’ sensitivity to environmental changes, then the stock of red grouper Epinephelus morio would be more affected by temperature increases than other species because it is the only fish population in the Campeche Bank currently assessed as overexploited.
      Citation: Fishes
      PubDate: 2022-06-29
      DOI: 10.3390/fishes7040156
      Issue No: Vol. 7, No. 4 (2022)
       
  • Fishes, Vol. 7, Pages 157: Modeling the Individual Growth of the
           Bonnethead Shark Sphyrna tiburo of the Western Gulf of Mexico Using the
           Multimodel Approach

    • Authors: Sandra Edith Olmeda-de la Fuente, Jorge Homero Rodríguez-Castro, Jose Alberto Ramírez-de León, Frida Carmina Caballero-Rico, Jorge Alejandro Rodríguez-Olmeda, Filiberto Toledano-Toledano
      First page: 157
      Abstract: To describe the growth pattern of the bonnethead shark (Sphyrna tiburo) in the Gulf of Mexico, a von Bertalanffy (VB) model has been automatically fit, which indicated a single−phase continuous growth without oscillations, though this would generate biases if this hypothesis is not confirmed. The objective of this research was to describe the growth pattern of S. tiburo under a multimodel approach based on information theory and contrasting single−phase models (VB, Gompertz, logistic models, and variants) and biphasic models (Soriano model and variants). The VB model was not supported. The Soriano model, with the variant in growth rate (k) and including length at birth (L0), was selected with 100% supporting evidence. The hypothesis of the two−phase growth of S. tiburo with an increase in k, more than L∞, fitted to L0, is confirmed, and a correspondence was identified between growth−phase change sizes and the sizes reported in the literature for change in the juvenile–adult stages in females and for onset of reproductive maturity in males and both sexes.
      Citation: Fishes
      PubDate: 2022-06-29
      DOI: 10.3390/fishes7040157
      Issue No: Vol. 7, No. 4 (2022)
       
  • Fishes, Vol. 7, Pages 158: Quality Evaluation of Kohaku Koi (Cyprinus
           rubrofuscus) Using Image Analysis

    • Authors: Mikhail A. Domasevich, Hideo Hasegawa, Tatsuya Yamazaki
      First page: 158
      Abstract: Quality evaluation of koi (Cyprinus rubrofuscus) is essential to the koi industry. However, the community has a lack of knowledge about the quality evaluation of koi and about features of koi which are valuable. During the “All Japan Nishikigoi Show” competition, a quality evaluation of koi was conducted by authoritative experts. In the present study, photos of participants of this competition were used for analysis to discover features affecting the quality of the Kohaku variety of koi. The HSVA color model was used to define and extract from image red and pale red coverage rates in Kohaku body coloration. Body aspect ratio, body proportions, red coverage rate, and pale red coverage rate were extracted using tools written in Python programming language. Analyses of the extracted data revealed the significant impact body aspect ratio (p < 0.001) and pale red coverage rate (p < 0.001) on Kohaku quality. A low body aspect ratio has a positive impact on Kohaku quality, while a high pale red coverage rate has a very strong negative impact on Kohaku quality. This study and its results can be an important foundation for further research about koi quality.
      Citation: Fishes
      PubDate: 2022-06-29
      DOI: 10.3390/fishes7040158
      Issue No: Vol. 7, No. 4 (2022)
       
  • Fishes, Vol. 7, Pages 159: Tissue-Specific and Differential Cold Responses
           in the Domesticated Cold Tolerant Fugu

    • Authors: Shuang Han, Shang Wei, Ruoyu Chen, Man Ni, Liangbiao Chen
      First page: 159
      Abstract: Domestication can be defined as the artificial selection in animals to achieve morphological, physiological, and developmental conformity to human needs, with the aim of improving various limitations in species under a human feeding environment. The future sustainability of aquaculture may rely partly on the availability of numerous domesticated fish species. However, the underlying adaptive mechanisms that result in the domestication of fish are still unclear. Because they are poikilothermic, temperature is a key environmental element that affects the entire life of fish, so studying the association between physiological and behavioral changes in low-temperature domesticated fish can provide a model for understanding the response mechanisms of fish under cold stress. Through 5 generations and 10 years of artificial selection at low temperatures, we used cold-tolerant fugu as a biological model to compare transcriptome changes in brain and liver tissues to study the effects of cold stress on fish. It was found that the expression of genes such as apoptosis, p53, oxidative phosphorylation, and mitochondrial β-oxidation in the brain of cold-tolerant fugu was significantly lower than the wild type due to cold stress, while excessive energy metabolism would lead to the production of reactive oxygen species (ROS) and exacerbate the brain damage, thus causing rollover and coma. Meanwhile, under cold stress, the signaling pathways involved in glycogenolysis and lipid metabolism, such as insulin signaling, adipocytokines, and mTOR signaling pathways, were significantly up-regulated in the liver of cold-tolerant fugu. Although the mitochondrial β-oxidation pathway was increased in cold-tolerant fugu liver tissues, the transcriptome was not enriched in apoptotic. These phenomena predict that in response to low-temperature conditions, cold-tolerant fugu employs a dynamic inter-organ metabolic regulation strategy to cope with cold stress and reduce damage to brain tissues.
      Citation: Fishes
      PubDate: 2022-06-30
      DOI: 10.3390/fishes7040159
      Issue No: Vol. 7, No. 4 (2022)
       
  • Fishes, Vol. 7, Pages 160: Optimizing Hard Clam Production in Taiwan by
           Accounting for Nonlinear Effects of Stocking Density and Feed Costs on
           Farm Output of Clams

    • Authors: Jie-Min Lee, Sheng-Hung Chen, Yi-Chung Lee, Jung-Fu Huang, Christian Schafferer, Chun-Yuan Yeh, Ti-Wan Kung
      First page: 160
      Abstract: Despite mass mortality, hard clams remain among the main cultured shellfish in Taiwan. Using cross-sectional data, this study applies threshold regression modeling with stocking density and feed costs as the threshold variables to explore the nonlinear relationship between input and output factors. The findings show that the production output levels may be increased by different combinations of factor inputs and variations in input factors. More specifically, the higher output levels may be achieved by increasing labor input while reducing capital input factors in farming households with a higher stocking density (HSD > 1,087,870 inds/ha) or higher feed cost (HFC > 13,889 NTD/ha). Farming households with a lower stocking density (LSD ≤ 1,087,870 inds/ha) may enhance production output levels by increasing feed input while reducing capital inputs. Moreover, the maximum output level of HSD and HFC farming households was estimated to reach 9255 kg/ha and 9807 kg/ha, respectively. Results of the production output simulation suggest that the feeding cost per hectare in LSD households should not exceed 25,119 NTD to avoid overfeeding, which may cause culture deterioration and lower survival rates. As such, farmers are advised to adjust their feed costs according to the stocking density to maximize production output.
      Citation: Fishes
      PubDate: 2022-07-01
      DOI: 10.3390/fishes7040160
      Issue No: Vol. 7, No. 4 (2022)
       
  • Fishes, Vol. 7, Pages 161: Identification of Proteins Responsible for High
           Activity of Cysteine Proteinase Inhibitor in the Blood of Nile Tilapia
           Oreochromis niloticus

    • Authors: Seong Hee Mun, Joon Yeong Kwon
      First page: 161
      Abstract: Cysteine proteinase inhibitors (CPIs) protect tissues and organs against cysteine proteinases in animal blood and have attracted much attention for use in food processing and medical sciences for humans and animals. Several CPI proteins, which include stefins, cystatins, kininogens, histidine-rich glycoproteins (HRG) and fetuins, have been identified and characterized in mammals. Fish blood also contains high CPI activity, but the identity of the major protein responsible for this activity has not been clarified. This study was conducted to screen CPI activity by examining papain inhibitory activity from various different tissues in Nile tilapia Oreochromis niloticus and to identify major proteins for the activity in the blood. CPI activity was highest in the serum among the tissues screened in this study (at least fourfold higher than in other tissues)(P < 0.05). Major proteins for CPI activity in serum were purified using a CNBr-activated sepharose 4B column, gel filtration and an ion exchange FPLC column. From these purifications, two proteins with strong CPI activity were isolated and partially sequenced. Based on their molecular weights and partial amino sequences, the two major proteins with CPI activity from the blood in this species were found to be fetuin B (60 kDa) and kininogen (54 kDa).
      Citation: Fishes
      PubDate: 2022-07-01
      DOI: 10.3390/fishes7040161
      Issue No: Vol. 7, No. 4 (2022)
       
  • Fishes, Vol. 7, Pages 162: Reproductive Biology of Yellowfin Tuna (Thunnus
           albacares) in Tropical Western and Central Pacific Ocean

    • Authors: Xiaofei Shi, Jian Zhang, Xiao Wang, Yixi Wang, Cheng Li, Jiangao Shi
      First page: 162
      Abstract: A total of 756 yellowfin tuna (Thunnus albacares) caught by a Chinese drifting longliner in the tropical western and central Pacific Ocean (WCPO) from May 2018 to March 2019 were investigated to describe the reproductive biology of the species. Generalized linear model and polytomous logistic regression for the ordinal response model were employed to assess the effects of biometric and spatiotemporal factors (such as individual fork length (FL), fishing depth, dissolved oxygen, and month) on the reproductive traits of yellowfin tuna. The results showed that FLs ranged from 87 to 163 cm, averaging 115.8 cm (SD = ±14.2) for females and 121.8 cm (SD = ±16.8) for males. The proportion of males in the sampled fish was 0.61 (SD = ±0.29), and larger males (>130 cm) were proportionally predominant. Analyses based on the monthly variation of the gonadosomatic index and monthly proportion of sexual maturity stages of the gonads showed that the main spawning period of yellowfin tuna lasts from September to December. In addition, the 50% first maturity FLs of males and females were 111.96 cm (SD = ±1.04) and 119.64 cm (SD = ±1.30), respectively. This study provides new information on the reproductive development of T. albacares in the tropical WCPO region. These reproductive parameters reduce uncertainty in current stock assessment models, which will ultimately assist the fishery in becoming sustainable for future generations.
      Citation: Fishes
      PubDate: 2022-07-02
      DOI: 10.3390/fishes7040162
      Issue No: Vol. 7, No. 4 (2022)
       
  • Fishes, Vol. 7, Pages 93: Descriptions of Two New Species, Sillago
           muktijoddhai sp. nov. and Sillago mengjialensis sp. nov. (Perciformes:
           Sillaginidae) from the Bay of Bengal, Bangladesh

    • Authors: Shilpi Saha, Na Song, Zhengsen Yu, Mohammad Abdul Baki, Roland J. McKay, Jianguang Qin, Tianxiang Gao
      First page: 93
      Abstract: Due to difficulty in recognition, many true species have been covered under the synonyms of wide-spread species. To justify the identification of a widely distributed species, Sillago sihama from the Bay of Bengal, Bangladesh, an integrated approach including morphology and DNA barcoding was used. Two unrecognized species of Sillago, i.e., Sillagomuktijoddhai sp. nov. and S. mengjialensis sp. nov., were identified from the coastal area of Bangladesh. S. muktijoddhai sp. nov. has marked differences in the body color, anal fin color, number of gill rakers, snout length, and swimbladder. S. mengjialensis sp. nov. has notable differences in the anal fin color, snout length, and swimbladder and is distinguished from S. muktijoddhai sp. nov. by the body color and swimbladder. The morphological characters of 14 documented Sillago species with two posterior extensions of the swimbladder were referenced and distinguished to accredit the two new species. Genetic analyses of partial mitochondrial cytochrome oxidase subunit I and 16S ribosomal RNA also supported the validity of the new species. This study has increased the number of recognized species of Sillago in the world and confirmed the prevailing misidentification of these two new species in Bangladesh as so-called S. sihama. Moreover, the study confirmed the misidentification of S. mengjialensis sp. nov. in Indonesia as S. sihama and the identification of unknown Sillago sp.1 in India.
      Citation: Fishes
      PubDate: 2022-04-19
      DOI: 10.3390/fishes7030093
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 94: Bacillus subtilis Supplementation in a High-Fat
           Diet Modulates the Gut Microbiota and Ameliorates Hepatic Lipid
           Accumulation in Grass Carp (Ctenopharyngodon idella)

    • Authors: Daoyuan Guo, Mengqi Xie, Hang Xiao, Lili Xu, Shiyu Zhang, Xiaoxuan Chen, Zhixin Wu
      First page: 94
      Abstract: To study the effects of Bacillus subtilis supplementation in a high-fat diet on the gut microbiota and nonalcoholic fatty liver disease in grass carp (Ctenopharyngodon idella), juveniles (60 ± 5 g) were fed three diets: (a) a control diet (CON), (b) a high-fat diet (HFD) and (c) a high-fat diet supplemented with B. subtilis (HFD + BS). After 8 weeks of feeding, fish growth, serum biochemical indices and total liver lipid content were measured, and gut microbiota analysis was performed using the MiSeq250 high-throughput sequencing platform. The results of this study showed that B. subtilis could improve growth and blood serum indices and reduce lipid deposition in the fish liver, preventing fatty liver disease. A grass carp model of fatty liver induced by a high-fat diet was successfully established. Moreover, B. subtilis altered the intestinal microbiota of HFD-fed grass carp, making it more similar to that of the control group. This study revealed the important effects of B. subtilis on grass carp with fatty liver induced by a high-fat diet and provides the foundation for the application of probiotics in grass carp farming.
      Citation: Fishes
      PubDate: 2022-04-19
      DOI: 10.3390/fishes7030094
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 95: Assessment of Coilia mystus and C. nasus in the
           Yangtze River Estuary, China, Using a Length-Based Approach

    • Authors: Lu Zhai, Zengguang Li, Yongbin Hu, Chengwei Huang, Siquan Tian, Rong Wan, Daniel Pauly
      First page: 95
      Abstract: An assessment of the stock status and historical changes in abundance of Coilia mystus and C. nasus in the Yangtze River Estuary, China, was carried out based on field surveys conducted in 2019–2020 and published length-frequency (L/F) data from earlier periods. These two species’ current and past relative biomasses (B/BMSY) were estimated using a length-based Bayesian biomass estimation method (LBB). The LLB method also estimated their asymptotic lengths (Linf), current and optimum mean lengths at first capture (Lc; Lopt_c), and their ratios of natural and fishing mortality to growth (M/K; F/K). In response to increasing fishing pressure, both species’ maximum lengths declined, along with their B/BMSY ratio, which declined for C. mystus from 1.7 in 1982 to 0.47 in 2020 and for C. nasus from 1.7 in 2006 (or earlier) to 0.17 in 2020. These assessments show that both of the two Coilia species are overfished, with C. nasus impacted more severely than C. mystus. The prospect for the recovery of these two species is briefly discussed. This contribution will help toward the management of the population of these two Coilia species and provides a basis for evaluating the effect of the 10-year fishing ban in the Yangtze River.
      Citation: Fishes
      PubDate: 2022-04-19
      DOI: 10.3390/fishes7030095
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 96: Blood Transcriptome Analysis Reveals Gene
           Expression Differences between Yangtze Finless Porpoises from Two
           Habitats: Natural and Ex Situ Protected Waters

    • Authors: Wang Liu, Denghua Yin, Danqing Lin, Yan Yan, Xiaoyan Zhu, Congping Ying, Jialu Zhang, Pao Xu, Kai Liu
      First page: 96
      Abstract: The Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis, YFP) is a critically endangered small odontocete species, mainly distributed in the middle and lower reaches of the Yangtze River, Poyang Lake, and Dongting Lake. Under the influence of human activities, many factors are threatening the survival and reproduction of YFPs in their natural habitat. Ex situ conservation is of great significance to strengthen the rescuing conservation of YFPs by providing suitable alternative habitats and promoting the reproduction and growth of the ex situ population. To reveal the differences in gene expression of YFPs in natural and ex situ protected waters, and to investigate the effects of environmental factors on YFPs and their mechanisms, we performed transcriptome sequencing for blood tissues of YFPs collected from natural waters and ex situ protected waters. Using RNA-seq we identified 4613 differentially expressed genes (DEGs), of which 4485 were up-regulated and 128 were down-regulated in the natural population. GO analysis showed that DEGs were significantly enriched in entries related to binding, catalytic activity, and biological regulation; KEGG analysis showed that DEGs were enriched mainly in signal transduction, endocrine system, immune system, and sensory system-related pathways. Further analysis revealed that water pollution in natural waters may affect the hormone secretion of YFPs by altering the expression pattern of endocrine genes, thus interfering with normal endocrine activities; noise pollution may induce oxidative stress and inflammatory responses in YFPs, thus impairing the auditory function of YFPs. This study provides a new perspective for further research on the effect of habitat conditions on the YFPs and suggests that improving the habitat environment may help in the conservation of YFPs.
      Citation: Fishes
      PubDate: 2022-04-21
      DOI: 10.3390/fishes7030096
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 97: Potential Efficiency of Earth Observation for
           Optimum Fishing Zone Detection of the Pelagic Sardinella aurita Species
           along the Mediterranean Coast of Egypt

    • Authors: Elham M. Ali, Naglaa Zanaty, Islam Abou El-Magd
      First page: 97
      Abstract: This research utilizes the efficiency of remotely sensed data and advanced digital image processing techniques to assist in monitoring for the management of marine fisheries in Egypt (south Mediterranean Sea region). A newly developed model is applied to the Sardinella aurita fisheries to determine optimal fishing zones, and is then applied to monitor and detect the potentially optimal fishing zones for other locally important and economic fish species. This approach depends on chlorophyll-a (Chl-a) and sea-surface temperature (SST) characteristics that are that known to control this species communities. The ranges and distribution of SST and Chl-a were obtained from Moderate Resolution Imaging Spectroradiometer (MODIS) aqua as well as Sentinel-3 satellites during the period from 2018 to 2020. The results revealed that there is a strong link between Sardinella abundance and both the SST and the Chl-a concentration. The suitable months for the abundance of this pelagic fish species were defined to be from May to November, producing 75% of the catch (nearly 42 K tons). Low abundances were recorded during the months from December to April, below the suitable harvest levels for this species. This research highlighted the importance of using satellite data as a tool to help scientists to develop appropriate management strategies for the sustainable management of fisheries resources worldwide.
      Citation: Fishes
      PubDate: 2022-04-22
      DOI: 10.3390/fishes7030097
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 98: Hematogenesis Adaptation to Long-Term Hypoxia
           Acclimation in Zebrafish (Danio rerio)

    • Authors: Linghui Shi, Lei Chen, Shouwen Jiang, Zhichao Wu, Yan Zhou, Qianghua Xu
      First page: 98
      Abstract: When fish live in the wild or are cultured artificially, they will inevitably suffer from hypoxia. At the same time, blood physiological indexes represent the physiological state of fish. In order to study the effect of long-term hypoxia acclimation on fish hematogenesis, we cultured zebrafish embryos into adulthood in a hypoxia incubator (1.5 ± 0.2 mg/L). Then we compared the hematological parameters of zebrafish cultured in normoxia and hypoxia conditions. Transcriptome sequencing analysis of the main hematopoietic tissue, the head kidney, was also compared between the two groups. Results showed that the number of erythrocytes increased significantly in the long-term hypoxia acclimated group, while the size of several cell types, such as red blood cells, eosinophils, basophils, small lymphocytes and thrombocytes, decreased significantly. The transcriptomic comparisons revealed that there were 6475 differentially expressed genes (DEGs) between the two groups. A Gene Ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that hematopoiesis and cell proliferation signaling were the most significantly enriched pathways in the head kidney of hypoxia acclimated zebrafish. In addition, many genes involved in the hematopoietic process showed significantly higher levels of expression in the hypoxia acclimated zebrafish, when compared to the normoxia zebrafish. When considered together, these data allowed us to conclude that long-term hypoxia can promote the hematopoiesis process and cell proliferation signaling in the zebrafish head kidney, which resulted in higher red blood cell production. Higher numbers of red blood cells allow for better adaptation to the hypoxic environment. In conclusion, this study provides a basis for the in-depth understanding of the effects of hypoxia on hematogenesis in fish species.
      Citation: Fishes
      PubDate: 2022-04-22
      DOI: 10.3390/fishes7030098
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 99: Comparative Otolith Morphology of Two Morphs of
           Schizopygopsis thermalis Herzenstein 1891 (Pisces, Cyprinidae) in a
           Headwater Lake on the Qinghai-Tibet Plateau

    • Authors: Jialing Qiao, Ren Zhu, Kang Chen, Dong Zhang, Yunzhi Yan, Dekui He
      First page: 99
      Abstract: Teleost otoliths provide a pivotal medium for studying changes in population structure and population dynamics of fish. Understanding the otolith-fish size relationship and intraspecies variation in otolith morphology is essential for the accurate assessment and management of fishery resources. In our study, we aimed to estimate the relationships between otolith morphological measurements and fish length, and detect differences in the otolith morphology of planktivorous and benthivorous morphs of Schizopygopsis thermalis in Lake Amdo Tsonak Co on the Qinghai-Tibet Plateau (QTP). Both morphs exhibited strong linear otolith-fish size relationships; otolith morphology was sexually dimorphic in each morph; the morphs differed significantly in otolith shape and size (e.g., posterior side, the region between the posterior and ventral otolith, otolith length, circularity, and surface density). In addition, we found that the differences in otolith morphology between morphs are related to habitat preferences, diet, and growth. Basic data on the biology of S. thermalis are essential for poorly studied Lake Amdo Tsonak Co, and our study emphasizes that intraspecific variation in otolith morphology should be taken into consideration when differentiating stocks, populations, and age classes based on otolith morphology.
      Citation: Fishes
      PubDate: 2022-04-26
      DOI: 10.3390/fishes7030099
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 100: Pre-Hatching Ontogenetic Changes of
           Morphological Characters of Small-Spotted Catshark (Scyliorhinus canicula)
           

    • Authors: Bianka Grunow, Theresa Reismann, Timo Moritz
      First page: 100
      Abstract: The small-spotted catshark, Scyliorhinus canicula, provides an optimal model organism to include chondrichthyans in studies comparing morphology or physiology through vertebrate evolution. In particular, for investigations with ontogenetic aspects, there are only a limited number of alternative taxa. Therefore, a detailed staging system is a prerequisite to allowing comparison between different studies. This study supplements information on the latest stages of the established system by Ballard and colleagues in 1993 and complements the respective staging system by including the latest pre-hatching stages. During this phase, some significant ontogenetic shifts happen, e.g., reduction of external gill filament length and complete flattening of rostral angle until Size Class 6, change in the ratio of pre- to post-vent length, and establishment of body pigmentation in Size Classes 7 and 8. All these shifts finally transform the embryo into a hatchling prepared for living outside the eggshell. This study provides a framework allowing comparison of investigations on pre-hatchings of the small-spotted catshark.
      Citation: Fishes
      PubDate: 2022-04-26
      DOI: 10.3390/fishes7030100
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 101: The Dynamics of Profitability among Salmon
           Farmers—A Highly Volatile and Highly Profitable Sector

    • Authors: Leiv Opstad, Johannes Idsø, Robin Valenta
      First page: 101
      Abstract: Salmon farming stands out from many other industries with its very high profitability, but it is also highly volatile. The main question is whether the profit of individual firms is stable, or whether profitable firms change from year to year. The purpose of this article is to apply the theory of profit persistence to answer this question for salmon farming in Norway. By using panel data from 2010 to 2019, available from public statistics, we study the relative deviation from the average profits. We estimate the speed of adjustment to the profit norm by using a dynamic GMM estimator. We find a high degree of convergence to the average profit among salmon farmers. For companies belonging to the group with below-average profit, there is a positive correlation between growth and profitability and a negative link between debt ratio and deviation of profit rate. Our finding is that although the Norwegian aquaculture industry has large profits, there is large volatility in the profits of this industry. This is useful knowledge for investors, lenders, public authorities and others who need to know something about the risk in the aquaculture industry.
      Citation: Fishes
      PubDate: 2022-04-27
      DOI: 10.3390/fishes7030101
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 102: Incorporation of Fisheries Policy into Regional
           Blocs'—Lessons from the EU’s Common Fisheries Policy

    • Authors: Shuo Li
      First page: 102
      Abstract: As globalization is facing increasing challenges, regionalization demonstrates the potential to effectively address many transboundary issues. Current international fisheries management has attracted criticisms, among which the poor incentives for countries to attend and comply with the rules are notable. This paper aims to explore whether the incorporation of fisheries policies into regional economic blocs can be a solution to improve cross-border fisheries management. The development, problems, and future of the Common Fisheries Policy (CFP) of the European Union are explored in detail. This paper concludes that the evolution and implementation of the CFP provide some precious lessons for the world. An appropriately designed regional fisheries scheme would help to create incentives for countries to participate in regional regimes and improve their fisheries management. Economic incentives, a good institutional design, and financial and scientific support are critical factors in favor of adopting common fisheries policies under regional economic frameworks.
      Citation: Fishes
      PubDate: 2022-04-28
      DOI: 10.3390/fishes7030102
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 103: Cytoprotective and Antigenotoxic Properties of
           Organic vs. Conventional Tomato Puree: Evidence in Zebrafish Model

    • Authors: Filomena Mottola, Renata Finelli, Marianna Santonastaso, Petronia Carillo, Lucia Rocco
      First page: 103
      Abstract: In this in vivo study, we investigated cytoprotective and antigenotoxic effects of commercial tomato puree obtained from conventional vs. organic farming systems (pesticides vs. pesticide-free agriculture, respectively). This is relevant as pesticides are widely used in agriculture to prevent pests, weeds, and the spread of plant pathogens. By exposing zebrafish to tomato puree alone and in combination with H2O2 (a well-known genotoxic agent), we analyzed the percentage of fish survival, cell viability, intracellular concentration of reactive oxygen species (ROS), DNA fragmentation index (DFI%), and genomic template stability (GTS%). Fish exposed to organic puree showed higher fish survival and cellular viability, lower DFI% and ROS, and improved GTS%. Our results suggest a higher cytoprotective and antigenotoxic effect of organic pesticide-free tomatoes, probably because the activity of natural phytochemicals is not affected by the presence of toxic residues, which are otherwise produced by pesticides used in conventional farming systems. Our study points out the importance of considering alternative strategies in agriculture to minimize the genotoxic impact of chemical pesticides.
      Citation: Fishes
      PubDate: 2022-04-29
      DOI: 10.3390/fishes7030103
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 104: The Reproductive Characteristics of Garra
           tibetana, an Endemic Labeonine Fish in the Lower Yarlung Tsangpo River,
           Tibet, China

    • Authors: Zheng Gong, Lin Chen, Jian Wang, Huanzhang Liu
      First page: 104
      Abstract: The reproductive characteristics of an endemic labeonine fish, Garra tibetana, were investigated by examining 778 individuals collected monthly, from December 2015 to November 2016, in the lower Yarlung Tsangpo River, Tibet, China. Results showed that females predominated in the overall population with a sex ratio of 1:0.73, while the sex ratio for the mature individuals was 1:1. Standard length at first maturity was estimated as 82.4 mm for females and 55.4 mm for males based on logistic regression. Analyses based on the monthly variation of the gonad-somatic index, monthly proportion of gonad development, and frequency distribution of oocyte diameter demonstrated the spawning period of G. tibetana to be from February to April, with a peak in March. Absolute fecundity ranged from 113 to 440 oocytes, with a mean of 201.8 ± 58.7 oocytes. The relative fecundity ranged from 6 to 18 oocytes per gram, with a mean of 11.7 ± 2.6 oocytes per gram. Absolute fecundity showed positive correlations with standard length, body weight, and gonad weight, revealing that larger females produced more offspring. In conclusion, G. tibetana matures early and spawns synchronously from February to April, with low fecundity and large oocytes. These reproductive characteristics could explain why this species is dominant in its habitat and also provide valuable information for developing applicable management and conservation strategies.
      Citation: Fishes
      PubDate: 2022-04-29
      DOI: 10.3390/fishes7030104
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 105: Somatic Condition and Reproductive Potential as
           a Tandem in European Sardine: An Analysis with an Environmental
           Perspective in the Northern Adriatic (Gulf of Trieste)

    • Authors: Marta Caballero-Huertas, Xènia Frigola-Tepe, Jordi Viñas, Marta Muñoz
      First page: 105
      Abstract: The European sardine’s condition is reflected in its reproductive potential, and therefore, in its status as a fishery resource. These values depend on the stock’s distribution and resource availability, which is highly determined by environmental characteristics. Sardines from the productive Gulf of Trieste (in the North Adriatic), located in the northernmost section of the most septentrional Mediterranean sub-basin in which sardine exploitation has traditionally been intensive, were analysed. The reproductive cycle and gonadosomatic index (GSI) were studied. Tissue and mesenteric fat values, as well as vacuity (% V), relative condition (Kn), and hepatosomatic (HSI) indices were evaluated due to their potential relationships with reproductive performance. The results suggested opposite patterns between fat reserves and GSI, while Kn showed a relationship neither with GSI, nor with reproductive stage, which led us to conclude that it is more advisable to apply direct lipid indices to project their contribution to reproductive potential. Moreover, the females’ condition was generally better than that of the males, added to an advanced gonadal development during spring and summer, albeit males and females reached the spawning season together. Moreover, females’ GSIs were significantly higher during active spawning. Furthermore, correlation analyses showed that SST was related with the parameters evaluated, as well as the available portion of productivity for the fish (OPFish), which may explain the sardines’ better condition and GSIs than their chlorophyll concentration.
      Citation: Fishes
      PubDate: 2022-05-04
      DOI: 10.3390/fishes7030105
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 106: Immuno-Enzymatic and Proteomic Approaches for
           Sexing the African Bonytongue (Heterotis niloticus Cuvier, 1829)

    • Authors: N’Zi Daniel Koua, Joël Henry, Erwan Corre, Julien Pontin, Benoît Bernay, Jésus Nunez
      First page: 106
      Abstract: Heterotis niloticus is an African species of Osteoglossiformes that presents biological peculiarities and zootechnical performances favorable for fish farming. However, the absence of a sexual dimorphism hinders the optimization of its reproduction in captivity and limits the understanding of its reproductive behavior. This study is aimed at developing a minimally invasive and reliable sexing method to detect vitellogenin (Vtg) in female plasma. A commercial sexing kit (Acobium, Montpellier, France) for Arapaima gigas—a phylogenetically sister species of H. niloticus—successfully identified only 20% of mature H. niloticus females. Enzyme-linked immunosorbent assays (ELISA) were carried out using three Vtg antibodies. The A. gigas Vtg1 antibody cross-reacted significantly with plasma dilutions of female H. niloticus ranging from 1:1000 to 1:10,000, but with relatively low intensity. The Vtg antibody from Osteoglossum bicirrhosum, another species of Osteoglossiformes, showed non-specific binding with the Vtg of H. niloticus female plasma. Finally, an antibody for H. niloticus Vtg developed in this study allowed us to differentiate the two sexes with plasma coating dilutions ranging from 1:1000 to 1:10,000. The results of the assay were validated by a proteomic approach showing that Vtg-targeted mass spectrometry analysis of H. niloticus blood protein extracts could be used to accurately determine the presence of Vtg in the plasma of mature females. The final validation of the ELISA technique using the H. niloticus Vtg antibody was confirmed by visual sexing of a significant number of blood-sampled fish gonads; 100% of the fish were correctly sexed by the ELISA method.
      Citation: Fishes
      PubDate: 2022-05-06
      DOI: 10.3390/fishes7030106
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 107: Intestinal Lipase Characterization in Common
           Snook (Centropomus undecimalis) Juveniles

    • Authors: Bartolo Concha-Frías, Martha Gabriela Gaxiola-Cortes, Fanny Janet De la Cruz-Alvarado, Luis Daniel Jimenez Martinez, Emyr Saul Peña-Marin, Marcia Angélica Oliva-Arriagada, Joe Luis Arias-Moscoso, Carlos Alfonso Alvarez-González
      First page: 107
      Abstract: The common snook (Centropomus undecimalis) is a euryhaline fish with high commercial demand in the Mexican southeast, Caribbean, and South America. However, some aspects of its digestive physiology are still unknown, particularly in relation to lipid hydrolysis. Therefore, the characterization of the digestive lipase of this species was carried out. Our results show that the digestive lipase’s optimal temperature is 35 °C, being stable between 25 and 35 °C, and shows maximum activity at pH 9, with stability between pH 5 and 8. Different degrees of inhibition were presented by Orlistat (61.4%), Ebelactone A (90.36%), Ebelactone B (75.9%), SDS 1% (80.7%), SDS 0.1% (73.5%), and SDS at 0.01% (34.9%). Orlistat and Ebelactone A and B completely inhibited the lipase band in the zymogram, but not SDS addition. Lipase showed a molecular weight of 43.8 kDa. The high lipase activities in the digestive tract indicate the importance of lipids in the diet of C. undecimalis.
      Citation: Fishes
      PubDate: 2022-05-10
      DOI: 10.3390/fishes7030107
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 108: Gastrointestinal Microbiota of Spiny Lobster: A
           Review

    • Authors: En Yao Lein, Mohammad Tamrin Mohamad Lal, Balu Alagar Venmathi Maran, Choon Looi Ch’ng, Katsuyuki Hamasaki, Motohiko Sano, Audrey Daning Tuzan
      First page: 108
      Abstract: The gastrointestinal (GI) microbiota is a group of complex and dynamic microorganisms present in the GI tract of an organism that live in symbiosis with the host and benefit the host with various biological functions. The communities of GI microbiota are formed by various aerobic, anaerobic, and facultatively anaerobic bacteria in aquatic species. In spiny lobsters, common GI microorganisms found in the GI tract are Vibrio, Pseudomonas, Bacillus, Micrococcus, and Flavobacterium, where the structure and abundance of these microbes are varied depending on the environment. GI microbiotas hold an important role and significantly affect the overall condition of spiny lobsters, such as secreting digestive enzymes (lipase, protease, and cellulase), helping in digesting food intake, providing nutrition and synthesising vitamins needed by the host system, and protecting the host against infection from pathogens and diseases by activating an immune mechanism in the GI tract. The microorganisms in the water column, sediment, and diet are primarily responsible for altering, manipulating, and shaping GI microbial structures and communities. This review also highlights the possibilities of isolating the indigenous GI microbiota as a potential probiotic strain and introducing it to spiny lobster juveniles and larvae for better health management.
      Citation: Fishes
      PubDate: 2022-05-11
      DOI: 10.3390/fishes7030108
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 109: The Lifetime Migratory History of Anadromous
           Brook Trout (Salvelinus fontinalis): Insights and Risks from
           Pesticide-Induced Fish Kills

    • Authors: Scott D. Roloson, Kyle M. Knysh, Sean J. Landsman, Travis L. James, Brendan J. Hicks, Michael R. van den Heuvel
      First page: 109
      Abstract: Brook trout populations in Prince Edward Island, Canada, have experienced over 50 pesticide-related fish kills since the 1960s. Life history evaluation of large sea-run brook trout recovered following two fish kill events was compared with a reference river using strontium:calcium otolith microchemistry. This study examined the dual hypotheses that anadromous brook trout are more likely to arise from sea-run mothers, and that freshwater entry timing makes them vulnerable to pesticide-induced fish kills. A total 89% of the fish exhibited an anadromous life history, and 77% of these were offspring of anadromous mothers, suggesting that anadromy is dominant in progeny of sea-run mothers. This study adds to our understanding of the maternal inheritance of anadromy in sea-run brook trout populations. Additionally, freshwater entry precedes the majority of fish kill events, illustrating that the overlap between migration and pesticide runoff contributes to the cumulative population risks to sea-run brook trout.
      Citation: Fishes
      PubDate: 2022-05-11
      DOI: 10.3390/fishes7030109
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 110: Effect of Culture Period and Stocking Density
           on Input Demand and Scale Economies of Milkfish (Chanos chanos)
           Polycultures with White Shrimp (Penaeus indicus)

    • Authors: Wei-Tse Pai, Christian Schafferer, Jie-Min Lee, Li-Ming Ho, Yung-Hsiang Lu, Han-Chung Yang, Chun-Yuan Yeh
      First page: 110
      Abstract: Milkfish, Chanos chanos, is one of the major inland cultured fish species in Taiwan. Variations in land resources and climate have led to the application of two distinct culture practices of milkfish polycultures with white shrimp, Penaeus indicus. This study applies a translog cost function model to analyze the production scale economy and input demand price elasticity of four milkfish polyculture systems with two different culture periods (OWC and NOWC) and two different white shrimp–milkfish fry stocking ratios (low SMR: 10–55 fry/ha; high SMR: 56–100 fry/ha). The findings show that the four milkfish polyculture systems require different operational adjustments to increase production while reducing the average culture cost. More specifically, overwinter cultures (OWC) have economies of scale. Farmers may reduce the average cost by expanding the production scale. Non-overwinter polycultures (NOWC) with high SMR are at the stage of decreasing return to scale, meaning that gains in output of milkfish cannot reduce the average cost. In terms of input factor use, farmers of OWC systems with high SMR are sensitive to fluctuations in the fry price since fry constitutes the input factor exhibiting the highest own-price elasticity. Moreover, fry and feed of OWC households with high SMR have high levels of substitutability, whereas fry and other input exhibit substitutability in OWC systems with low SMR. In NOWC farming households with high SMR, fry and capital have substitutability. It is thus recommended to modify the input factor use according to the culture mode and the white shrimp–milkfish stocking density ratio. Moreover, the study found that NOWCs have considerably higher SMR than OWCs, which may lead to a deterioration of the water quality in NOWC fishponds and lower survival rates. It is thus recommended to reduce the SMR to 31:1 to achieve economies of scale in production and increase the survival rate of milkfish and white shrimp.
      Citation: Fishes
      PubDate: 2022-05-11
      DOI: 10.3390/fishes7030110
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 111: Neuropeptide Y in Spotted Scat (Scatophagus
           Argus), Characterization and Functional Analysis towards Feed Intake
           Regulation

    • Authors: Daniel Assan, Yaorong Wang, Umar Farouk Mustapha, Charles Brighton Ndandala, Zhiyuan Li, Guang-Li Li, Huapu Chen
      First page: 111
      Abstract: Neuropeptide Y (Npy) is an intricate neuropeptide regulating numerous physiological processes. It is a highly conserved peptide known to improve feed intake in many vertebrates, including fishes. To enlighten the mechanism of Npy in spotted scat feed intake control, we cloned and identified the Npy cDNA sequence. We further examined its expression in some tissues and explored its expression effects at different time frames (hours and days). Here, we discovered that spotted scat Npy comprised a 300 bp open reading frame (ORF) and a 99 amino acid sequence. Npy was identified to be expressed in all tissues examined. Using in situ hybridization examination, we proved that npy has a wide expression in the brain of the spotted scat. Furthermore, the expression of npy in the hypothalamus significantly increased one hour after feeding (p < 0.05). Further, it was revealed that npy expression significantly increased in fish that were fasted for up to 5 days and significantly increased after refeeding from the 8th to the 10th day. This suggests that Npy is an orexigenic peptide, and hence, it increases food intake and growth in the spotted scat. Additionally, results from in vitro and in vivo experiments revealed that Npy locally interacts with other appetite-regulating peptides in the spotted scat hypothalamus. This research aimed to set a fundamental study in developing the feed intake regulation, improving growth and reproduction, which is significant to the aquaculture industry of the spotted scat.
      Citation: Fishes
      PubDate: 2022-05-12
      DOI: 10.3390/fishes7030111
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 112: Inter-Otolith Differences in Strontium
           Markings: A Case Study on the Juvenile Crucian Carp Carassius carassius
           (Linnaeus, 1758)

    • Authors: Yahua Zhu, Tao Jiang, Xiubao Chen, Hongbo Liu, Quinton Phelps, Jian Yang
      First page: 112
      Abstract: The release of hatchery-reared fish fry for restocking is important for the enrichment of fishery resources; however, the effective evaluation of the success rate of marking such fish is challenging. We exposed juvenile crucian carp (Carassius carassius) to a single concentration of SrCl2·6H2O for 5 d and evaluated the efficiency of Sr marking of the fish otoliths (sagittae, asterisci, and lapilli) using an electron probe micro-analyzer. Sr marking signatures formed a peak in all otolith types, with a marking success rate of 100%. The ratio of Sr to Ca in the lapilli and sagittae was higher than that in the asterisci. It took 2 d from the beginning of immersion to the deposition of Sr on the lapilli and sagittae, and the time delay for asterisci was 1 d. For the lapilli and sagittae, it took 16 d to terminate Sr marking and fully recover to the pre-marking Sr level, whereas it was 12 d for the asterisci. The application of the Sr dose had no effect on the survival or growth of the carp. This study demonstrated that the lapilli are the most suitable otolith type for Sr marking observations in crucian carp and provides a theoretical basis and technical support for carp restocking using the Sr marking approach.
      Citation: Fishes
      PubDate: 2022-05-15
      DOI: 10.3390/fishes7030112
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 113: Utilization of Fishery-Processing By-Product
           Squid Pens for Scale-Up Production of Phenazines via Microbial Conversion
           and Its Novel Potential Antinematode Effect

    • Authors: Thi Hanh Nguyen, San-Lang Wang, Thi Huyen Nguyen, Manh Dung Doan, Thi Ha Trang Tran, Van Anh Ngo, Nhat Duoc Ho, Thi Ngoc Tran, Chien Thang Doan, Van Chung Do, Anh Dzung Nguyen, Van Bon Nguyen
      First page: 113
      Abstract: Fishery by-products (FBPs) have been increasingly investigated for the extraction and production of a vast array of active molecules. The aim of this study was to produce phenazine compounds from FBPs via microbial fermentation and assess their novel antinematode effect. Among various FBPs, squid pen powder (SPP) was discovered as the most suitable substrate for phenazine production by Pseudomonas aeruginosa TUN03 fermentation. Various small-scale experiments conducted in flasks for phenazine production indicated that the most suitable was the newly designed liquid medium which included 1% SPP, 0.05% MgSO4, and 0.1% Ca3(PO4)2 (initial pH 7). Phenazines were further studied for scale-up bioproduction in a 14 L bioreactor system resulting in a high yield (22.73 µg/mL) in a much shorter cultivation time (12 h). In the fermented culture broth, hemi-pyocyanin (HPC) was detected as a major phenazine compound with an area percentage of 11.28% in the crude sample. In the bioactivity tests, crude phenazines and HPC demonstrate novel potential nematicidal activity against black pepper nematodes, inhibiting both juveniles (J2) nematodes and egg hatching. The results of this work suggest a novel use of SPP for cost-effective bioproduction of HPC, a novel potential nematodes inhibitor. Moreover, the combination of MgSO4 and Ca3(PO4)2 was also found to be a novel salt composition that significantly enhanced phenazine yield by P. aeruginosa fermentation in this work.
      Citation: Fishes
      PubDate: 2022-05-15
      DOI: 10.3390/fishes7030113
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 114: The Fishery Value Chain Analysis in Taiwan

    • Authors: Tsung-Yu Yang, Hsing-Chun Lin, Wen-Hong Liu
      First page: 114
      Abstract: Although the GDP of the fishery sector accounts for less than 0.3% of Taiwan’s GDP, there are many secondary and tertiary industries related to fisheries that add great value to the country’s economy. Therefore, when analyzing and calculating the output value and value added of the fishery sector, the relevance of these upstream and downstream industries should be considered jointly, and the value chain of the fishery industry should be studied and analyzed in order to truly present the value added created by fishery. This study aims to do this by first analyzing not only the primary fishery industry, but the value chain of the fishery industry at different stages such as fishery production, marine fishing, aquaculture, fishery processing, retail and services, and supportive systems. Then the value added of the whole fishery value chain to Taiwan’s GDP is estimated by using the Leontief input–output model, from the perspective of industry linkages and covering the period from 2011 to 2018. The empirical results suggest that the value added created by fishery and related industries accounted for 2.96% of the GDP in 2011, which rose to 3.11% in 2014, fell to 2.87% in 2015, rose to 2.93% in 2017, and fell to 2.84% in 2018. From 2011 to 2018, the amount of value added created by fisheries and related industries rose from NT$ 422.8 billion to NT$ 520.9 billion. The primary fishery sector has the largest contribution, followed by the fishery input sector, and transportation and sale service sector, and the fishery product processing sector has the lowest contribution rate. The empirical results provide important implications and references to the policy makers.
      Citation: Fishes
      PubDate: 2022-05-16
      DOI: 10.3390/fishes7030114
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 115: Transcriptome Sequencing Analysis Reveals
           Dynamic Changes in Major Biological Functions during the Early Development
           of Clearhead Icefish, Protosalanx chinensis

    • Authors: Xuemei Tang, Shulun Jiang, Henglin Wang, Yanfeng Zhou, Fei Peng, Xizhao Zhang, Yifan Zhou, Shiyue Guo, Yang You
      First page: 115
      Abstract: Early development, when many important developmental events occur, is a critical period for fish. However, research on the early development of clearhead icefish is very limited, especially in molecular research. In this study, we aimed to explore the dynamic changes in the biological functions of five key periods in clearhead icefish early development, namely the YL (embryonic), PM (first day after hatching), KK (fourth day after hatching), LC (seventh day after hatching), and SL (tenth day after hatching) stages, through transcriptome sequencing and different analysis strategies. A trend expression analysis and an enrichment analysis revealed that the expression ofgenes encoding G protein-coupled receptors and their ligands, i.e., prss1_2_3, pomc, npy, npb, sst, rln3, crh, gh, and prl that are associated with digestion and feeding regulation gradually increased during early development. In addition, a weighted gene co-expression network analysis (WGCNA) showed that eleven modules were significantly associated with early development, among which nine modules were significantly positively correlated. Through the enrichment analysis and hub gene identification results of these nine modules, it was found that the pathways related to eye, bone, and heart development were significantly enriched in the YL stage, and the ccnd2, seh1l, kdm6a, arf4, and ankrd28 genes that are associated with cell proliferation and differentiation played important roles in these developmental processes; the pak3, dlx3, dgat2, and tas1r1 genes that are associated with jaw and tooth development, TG (triacylglycerol) synthesis, and umami amino acid receptors were identified as hub genes for the PM stage; the pathways associated with aerobic metabolism and unsaturated fatty acid synthesis were significantly enriched in the KK stage, with the foxk, slc13a2_3_5, ndufa5, and lsc2 genes playing important roles; the pathways related to visual perception were significantly enriched in the LC stage; and the bile acid biosynthetic and serine-type peptidase activity pathways were significantly enriched in the SL stage. These results provide a more detailed understanding of the processes of early development of clearhead icefish.
      Citation: Fishes
      PubDate: 2022-05-21
      DOI: 10.3390/fishes7030115
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 116: Climate Risks and Opportunities of the Marine
           Fishery Industry: A Case Study in Taiwan

    • Authors: Ching-Hsien Ho
      First page: 116
      Abstract: As climate change and extreme weather intensify, forecasting natural environmental changes involves high uncertainty and variation. Planned policy changes and the ability of fisheries to withstand these changes and impacts are major challenges in regard to addressing future climate hazards in Taiwan. Taiwan’s geographic location is favourable for the marine fishery industry, which is an important primary industry and a source of animal protein for residents of Taiwan. Recently, both long-term climate change and extreme climate hazards have led to shocks in the marine fishery industry. The resulting instability of the industry directly affects the market supply of and demand for seafood. We conduct a case study of a marine fishery industry in Taiwan that incorporates social concern assessments of risk perception and judgements of risk acceptance through risk management processes. Furthermore, we incorporate stakeholder participatory processes to reduce the gap in awareness of adaptation and to increase the opportunity to reach consensus and develop an integrated risk management model that enables decision-makers to better meet the needs of society. These measures will enhance all parties’ willingness to adapt and help achieve the goal of public–private collaboration in facing climate change challenges.
      Citation: Fishes
      PubDate: 2022-05-21
      DOI: 10.3390/fishes7030116
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 117: Development of the First Microsatellite
           Multiplex PCR Panel for Meagre (Argyrosomus regius), a Commercial
           Aquaculture Species

    • Authors: Antonio Vallecillos, Emilio María-Dolores, Javier Villa, Francisco Miguel Rueda, José Carrillo, Guillermo Ramis, Mohamed Soula, Juan Manuel Afonso, Eva Armero
      First page: 117
      Abstract: In this study, a microsatellite-based multiplex PCR panel for meagre (Argyrosomus regius) was developed as a useful and single tool in parental assignment and population studies. Twenty-one specific and interspecific microsatellites from different aquaculture species of meagre (Argyrosomus regius), Japanese meagre (A. japonicus), red drum (Sciaenops ocellatus) and yellow meagre (Acoupa weakfish) were assessed for genetic variability, allelic range and genotype reliability. Finally, a SuperMultiplex for Argyrosomus regius (SMAr) was designed with only the best eight microsatellite markers. The panel assessment was performed using a batch of brood stock from one company and a sample of 616 offspring. It was possible to assign 95% of the offspring to a single pair of parents using the exclusion method. It is therefore considered an easy procedure, and a powerful and low-cost tool for parental assignment to support companies’ breeding programs and to exchange information between research groups.
      Citation: Fishes
      PubDate: 2022-05-24
      DOI: 10.3390/fishes7030117
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 118: Functional Characterization and Molecular
           Marker Development of the Proenkephalin as Biomarker of Food Addiction in
           Food Habit Domestication of Mandarin Fish (Siniperca Chuatsi)

    • Authors: Yingcen Li, Yunliang Miao, Xufang Liang, Shan He
      First page: 118
      Abstract: Proenkephalin (PENK), as the precursor of endogenous opioid enkephalin (ENK), is widely present in the nervous system and plays an important role in animal food addiction and rewarding behavior. In our study, we intend to study the functional characterization and molecular marker development of the penk gene related to food habit domestication of mandarin fish. We found that the penk gene of mandarin fish had three types of endogenous opioid peptide sequences. Compared with other tissues, penk mRNA was highly expressed in the whole brain. Intracerebroventricular (ICV) injection of lysine or methionine significantly increased the expression of penk mRNA. The expression of penk mRNA in the brain of mandarin fish that could be easily domesticated from eating live prey fish to artificial diets was significantly higher than those that could not. After feeding with high-carbohydrate artificial diets, the expression of penk mRNA showed no significant difference between mandarin fish with hypophagia and those that still ate normally. A total of four single nucleotide polymorphisms (SNP) loci related to easy domestication toward eating artificial diets were screened from the mandarin fish population. Additionally, the TT genotype at one of the loci was significantly correlated with the food habit domestication of mandarin fish.
      Citation: Fishes
      PubDate: 2022-05-27
      DOI: 10.3390/fishes7030118
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 119: Isolation, Identification and Characteristics
           

    • Authors: Mingyang Xue, Zidong Xiao, Yiqun Li, Nan Jiang, Wenzhi Liu, Yan Meng, Yuding Fan, Lingbing Zeng, Yong Zhou
      First page: 119
      Abstract: The largemouth bass (Micropterus salmoides) is one of the most economically valuable fish species in China. In this study, a bacterial pathogen was isolated from the internal organs of diseased M. salmoides, and the strain was named WH21406. This isolate was identified as Aeromonas caviae on the basis of its morphology, biochemical features and 16S rDNA phylogenetic analysis. Four virulence genes related to pathogenicity, namely, flagella (fla), elastase (ela), haemolysin (hly) and aerolysin (aer), were detected in this isolate. The median lethal dosage (LD50) of A. caviae WH21406 for M. salmoides was calculated to be 3.46 × 105 CFU mL−1. The histopathological analysis showed obvious tissue damage in the gill, liver, kidney, spleen and gut of the diseased fish. The antibiotic susceptibility test demonstrated that strain WH21406 was highly sensitive to enrofloxacin, norfloxacin, streptomycin and amikacin. The results of this study provide a foundation for the diagnosis, prevention and treatment of A. caviae infection in M. salmoides.
      Citation: Fishes
      PubDate: 2022-05-28
      DOI: 10.3390/fishes7030119
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 120: Basic Intersexuality (Abnormal Hermaphroditism)
           in the Blackmouth Catshark, Galeus melastomus, (Rafinesque, 1810), from
           the Southern Tyrrhenian Sea (Central Mediterranean Sea)

    • Authors: Claudio D’Iglio, Marco Albano, Sergio Famulari, Nunziacarla Spanò, Paola Rinelli, Serena Savoca, Gioele Capillo
      First page: 120
      Abstract: The present paper represents the first description of abnormal hermaphroditism in Galeus melastomus (Rafinesque, 1810). The black mouth cat shark specimen, collected in summer from southern Tyrrhenian Sea at the entrance of Salerno gulf, showed a basic intersexuality characterized by the presence of male secondary and female primary sexual characters. The reproductive system has been described with an accurate morphological analysis, also including a histological assessment of oocytes. Results showed the presence of only right clasper, not exceeding the pelvic fin in length, with the absence of internal males’ sexual organs. Concerning the female primary characters, the analysis of histological assessment showed the structure of mature oocyte, confirming the maturity stage of a mature female in active extruding stage, as highlighted by the macroscopic morphological analysis. Despite in many marine organisms’ hermaphroditism is a physiological condition showed by specimens during their lifecycle, in Elasmobranchs this is considered an abnormal condition, with some exceptions. The lack of information on hermaphroditism in elasmobranchs form the Mediterranean Sea requires an increase of scientific community’s attention, improving the knowledge on the reproductive biology of this sensitive taxon. This is essential to enhance the conservation of elasmobranchs populations in the entire Mediterranean basin.
      Citation: Fishes
      PubDate: 2022-05-28
      DOI: 10.3390/fishes7030120
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 121: DeepOtolith v1.0: An Open-Source AI Platform
           for Automating Fish Age Reading from Otolith or Scale Images

    • Authors: Dimitris V. Politikos, Nikolaos Sykiniotis, Georgios Petasis, Pavlos Dedousis, Alba Ordoñez, Rune Vabø, Aikaterini Anastasopoulou, Endre Moen, Chryssi Mytilineou, Arnt-Børre Salberg, Archontia Chatzispyrou, Ketil Malde
      First page: 121
      Abstract: Every year, marine scientists around the world read thousands of otolith or scale images to determine the age structure of commercial fish stocks. This knowledge is important for fisheries and conservation management. However, the age-reading procedure is time-consuming and costly to perform due to the specialized expertise and labor needed to identify annual growth zones in otoliths. Effective automated systems are needed to increase throughput and reduce cost. DeepOtolith is an open-source artificial intelligence (AI) platform that addresses this issue by providing a web system with a simple interface that automatically estimates fish age by combining otolith images with convolutional neural networks (CNNs), a class of deep neural networks that has been a dominant method in computer vision tasks. Users can upload otolith image data for selective fish species, and the platform returns age estimates. The estimates of multiple images can be exported to conduct conclusions or further age-related research. DeepOtolith currently contains classifiers/regressors for three fish species; however, more species will be included as related work on ageing will be tested and published soon. Herein, the architecture and functionality of the platform are presented. Current limitations and future directions are also discussed. Overall, DeepOtolith should be considered as the first step towards building a community of marine ecologists, machine learning experts, and stakeholders that will collaborate to support the conservation of fishery resources.
      Citation: Fishes
      PubDate: 2022-05-29
      DOI: 10.3390/fishes7030121
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 122: The Effect of Hormonal Treatment on Selected
           Sperm Quality Parameters and Sex Steroids in Tropical Cyprinid Bala Shark
           Balantiocheilos melanopterus

    • Authors: Peter Podhorec, Jindřiška Knowles, Jakub Vysloužil, Sergii Boryshpolets, Anatolii Sotnikov, Martina Holická, Jan Kouřil, Borys Dzyuba
      First page: 122
      Abstract: Hormone treatments are routinely employed with bala shark Balantiocheilos melanopterus male broodstock to stimulate the production of high-quality sperm. In the current trial, three spermiation-inducing treatments were evaluated: 20 μg/kg body weight (BW) recombinant hCG; 20 μg/kg BW [D-Ala6, Pro9, NEt]- gonadotropin-releasing hormone (GnRHa) with 20 mg/kg BW metoclopramide; and poly(lactic-co-glycolic acid) (PLGA) microparticles with slow release of 10 μg/kg BW GnRHa. A 0.9% saline AS negative control was also included. Administration of the GnRHa through the form of slow release of PLGA microparticles 24 h after treatment resulted in a significantly higher sperm volume, motility percentage, and total sperm count compared to the control. Injection of GnRHa with metoclopramide induced sperm parameters that did not differ from the control, with the exception of motility percentage. The lowest potency to induce spermiation in bala sharks was in the treatment with recombinant hCG. Both PLGA microparticles and GnRHa with metoclopramide significantly increased blood plasma concentrations of testosterone and 11-ketotestosterone compared to the control. The PLGA microparticle system with continuous release of 10 μg/kg BW GnRHa was the most effective treatment in inducing spermiation in bala sharks.
      Citation: Fishes
      PubDate: 2022-05-30
      DOI: 10.3390/fishes7030122
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 123: Fidelity to Natal Tributary Streams by Kokanee
           Following Introduction to a Large Oligotrophic Reservoir

    • Authors: J. Mark Shrimpton, Paige W. Breault, Luc A. Turcotte
      First page: 123
      Abstract: The WAC Bennett Dam was completed in 1968 and impounded the Upper Peace River to form the Williston Reservoir in north central British Columbia. In 1990, an enhancement project was initiated to stock Columbia River Kokanee (non-anadromous Sockeye Salmon; Oncorhynchus nerka) from southeastern British Columbia into tributary streams that drained into regions of the reservoir that were accessible by anglers. The current distribution of spawning Columbia-origin Kokanee in the Williston Reservoir watershed, however, does not reflect the locations where these fish were initially stocked and suggests extensive straying. Whether or not Kokanee will develop fidelity to specific spawning locations is not known, but it is important information to effectively manage these introduced fish. We used otolith microchemistry to estimate fidelity to natal streams by Columbia-origin Kokanee in the Williston Reservoir. Otolith elemental signatures for the region of the otolith that formed during the larval period and characterized the natal redd environment showed considerable variation among samples. Natal signatures tended to cluster for each river but not for all spawners, suggesting elemental signatures from other rivers. Homing to one of the four natal streams we examined was classified to be 73% based on linear discriminant analysis, although variation in the elemental signatures within each group suggests that homing by Kokanee to specific natal streams may be as low as 55%. Based on similarity of water elemental signatures for tributaries within large rivers, however, the proportion of fish that returned to their general region was likely higher and estimated to be approximately 83%. The result of regional homing could be reproductive isolation and adaptation to local conditions. It is unclear, however, if the current estimated level of straying will limit genetic differentiation and prevent local adaptation.
      Citation: Fishes
      PubDate: 2022-05-30
      DOI: 10.3390/fishes7030123
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 124: Long-Term Change of a Fish-Based Index of
           Biotic Integrity for a Semi-Enclosed Bay in the Beibu Gulf

    • Authors: Li Su, Youwei Xu, Yongsong Qiu, Mingshuai Sun, Kui Zhang, Zuozhi Chen
      First page: 124
      Abstract: The Beibu Gulf in the northwestern South China Sea is one of the world’s most productive fishing grounds, yet its biotic resources appear to be in rapid decline because of overexploitation. Assessments of the health status of the fisheries’ resources in the gulf provide a foundation for their conservation and management. As fish accounted for 84% to 97% of the total catch in the Beibu Gulf in the period 1962–2017, a Fish-based Index of Biotic Integrity (F-IBI) was developed for the Beibu Gulf, and data from otter trawl surveys during the period 1962–2017 were used to measure variations in the fish community. The assessment revealed a generally downward trend in total fish catch density (kg/km2), catch density of 12 traditional commercial demersal fish species, and percentage of nektonic-feeding species, but an upward trend for the percentage of fishes with a planktivorous or detritus diet, percentage of pelagic species, and percentage of the dominant species. The dominant species varied greatly over the 50 year period and showed a tendency towards small-sized species. The synthetic F-IBI variable showed a downward trend and has indicated a ‘fair’ state since 1998. The decline in the F-IBI over the last three decades suggests that anthropogenic disturbances, especially overfishing, have had a serious impact on the fish community of the Beibu Gulf. The F-IBI is currently at risk of becoming ‘poor.’ Consequently, we suggest that rigid and enforceable fishery management measures should be taken by both China and Vietnam to prevent further deterioration of the fisheries’ resources in the gulf.
      Citation: Fishes
      PubDate: 2022-05-30
      DOI: 10.3390/fishes7030124
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 125: Infectivity and Transmissibility of Acute
           Hepatopancreatic Necrosis Disease Associated Vibrio parahaemolyticus in
           Frozen Shrimp Archived at −80 °C

    • Authors: Chorong Lee, Hye Jin Jeon, Bum Keun Kim, Seong-Kyoon Choi, Sumi Kim, Gwang Il Jang, Ji Hyung Kim, Jee Eun Han
      First page: 125
      Abstract: Acute hepatopancreatic necrosis disease (AHPND) caused by Vibrio parahaemolyticus (VpAHPND) has been reported in commodity shrimp, but the potential risk of its global spread via frozen shrimp in the shrimp trade is yet to be fully explored. We hypothesized that frozen shrimp with AHPND could be a source of VpAHPND transmission; thus, the infectivity of frozen shrimp with AHPND was evaluated using a shrimp bioassay. To prepare infected frozen shrimp, 12 Penaeus vannamei (average weight, 2 g) were exposed to VpAHPND by immersion in water with a VpAHPND concentration of 1.55 × 107 CFU mL−1; once dead, the shrimp were stored at −80 °C for further analysis. After two weeks, a PCR assay was used to confirm AHPND positivity in frozen shrimp (n = 2), and VpAHPND was reisolated from the hepatopancreases of these shrimp. For the infectivity test, 10 P. vannamei (average weight, 4 g) were fed with the hepatopancreases of VpAHPND -infected frozen shrimp (n = 10). After feeding, 70% of the shrimp died within 118 h, and the presence of VpAHPND was confirmed using a PCR assay and histopathology examination; moreover, VpAHPND was successfully reisolated from the hepatopancreases of the dead shrimp. We are the first to evaluate the potential transmissibility of VpAHPND in frozen shrimp, and our results suggest that frozen shrimp with AHPND are a potential source of disease spreading between countries during international trade.
      Citation: Fishes
      PubDate: 2022-05-30
      DOI: 10.3390/fishes7030125
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 126: Suspended Structures Reduce Variability of
           Group Risk-Taking Responses of Dicentrarchus labrax Juvenile Reared in
           Tanks

    • Authors: Pablo Arechavala-Lopez, Samira Nuñez-Velazquez, Carlos Diaz-Gil, Guillermo Follana-Berná, João L. Saraiva
      First page: 126
      Abstract: Structural enrichment is considered a useful tool to improve the welfare conditions of captive fish by deliberately increasing the physical heterogeneity and complexity of captivity environments. However, the potential effects of structural enrichment on the stress response at the group level and on social interactions have not been well studied yet. In this study, we demonstrate that suspended vertical structures (U-shaped ropes) can reduce behavioural variability among fish groups (tank level) of European seabass (Dicentrarchus labrax) juveniles. Differences in behavioural responses during group risk-taking tests (e.g., number of passes per fish) between treatments were detected, and these responses in seabass in enriched captive conditions were more homogeneous among tanks compared to fish from non-enriched tanks. These results suggest a positive effect of the structural enrichment on social stabilisation and response to stressful events at the tank level in seabass. However, further research is still needed to improve the knowledge of the potential effects of structural enrichment on fish welfare and aquaculture management, considering different enrichment designs, intensities, and strategies according to farming conditions, biological needs, and preferences of the fish species and life-stage reared in captivity.
      Citation: Fishes
      PubDate: 2022-05-31
      DOI: 10.3390/fishes7030126
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 127: Inclusion of Mannan-Oligosaccharides in Diets
           for Tropical Gar Atractosteus tropicus Larvae: Effects on Growth,
           Digestive Enzymes, and Expression of Intestinal Barrier Genes

    • Authors: Claudia I. Maytorena-Verdugo, Emyr S. Peña-Marín, Carina S. Alvarez-Villagómez, Graciela M. Pérez-Jiménez, César A. Sepúlveda-Quiroz, Carlos A. Alvarez-González
      First page: 127
      Abstract: Mannan-oligosaccharides (MOS) are non-digestible carbohydrates, and their use in aquaculture as prebiotics is well documented. The objective of this work was to test whether MOS supplemented in the diet of A. tropicus larvae (2, 4, and 6 g kg−1) influence growth parameters, the activity of digestive enzymes, and the expression of genes related to the intestinal barrier. The highest total length was observed in larvae fed 6 g kg−1 MOS compared to control larvae. Trypsin activity increased with the addition of MOS to the diets, but leucine aminopeptidase activity only increased with 6 g kg−1 MOS. Lipase and α-amylase activities increased in larvae fed with 2 and 4 g kg−1 MOS. The expression of zo-2 was higher with the 6 g kg−1 MOS treatment. The cl-3 transcripts were lower with 2 g kg−1 MOS but higher with 6 g kg−1 MOS. All tested concentrations of MOS increased the expression of muc-2. In this study, incorporating mannan-oligosaccharides into the diet of A. tropicus larvae had a positive effect, and the concentration of 6 g kg−1 produced the best results. Therefore, including this prebiotic in the diets for the culture of A. tropicus larvae is suitable.
      Citation: Fishes
      PubDate: 2022-05-31
      DOI: 10.3390/fishes7030127
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 128: Taste Attributes of the “June Hairy
           Crab” Juveniles of Chinese Mitten Crab (Eriocheir sinensis) in
           Yangcheng Lake, China—A Pilot Study

    • Authors: Hongbo Liu, Junren Xue, Jing Tang, Tao Jiang, Xiubao Chen, Jian Yang
      First page: 128
      Abstract: This is the first report on the use of a taste sensing system to quantitatively evaluate the taste attributes of two groups of native “June hairy crab” juveniles (commonly referred to as “Liu-Yue-Huang”) of the Chinese mitten crab (Eriocheir Sinensis H. Milne Edwards, 1853) from a net enclosure culture area in Yangcheng Lake (lake culture) and aquaculture ponds near the lake (pond culture). We showed that umami was the predominant basic taste of steamed June hairy crabs, followed by bitterness and astringency. The intensity value of saltiness was aberrant and could not be determined using this system. The average values of aftertaste-U reached 8.7 and 10.7 in the male June hairy crabs from the lake and pond cultures, respectively, which was significantly higher than their respective aftertaste-B and aftertaste-A values (p < 0.01). Female crabs did not have aftertaste-B, while their aftertaste-U was significantly higher than aftertaste-A (p < 0.01). Although principal component analysis and linear discriminant analysis were not able to completely distinguish among crabs from different cultures, they could robustly distinguish between male and female crabs.
      Citation: Fishes
      PubDate: 2022-05-31
      DOI: 10.3390/fishes7030128
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 129: The miR-200 Family Targeting amh Affects the
           Gonadal Development of Japanese Flounder

    • Authors: Haoran Zhang, Kun Li, Fayang Zhang, Jikui Wu, Junling Zhang
      First page: 129
      Abstract: Four members of the miR-200 family in Japanese flounder (Paralichthys olivaceus) have sex-biased expression patterns, but their target genes and how they work in the development of the gonads are rarely known. Anti-Müllerian hormone (AMH) can inhibit the development of Muller’s duct in female mammals and regulate the formation of gametes after sexual maturity. There is no Muller’s duct in teleosts, but the amh gene still exists. Knockout of amh results in sex reversal from male to female. Therefore, it is essential to explore the relationship between the miR-200 family and amh to clarify what role miR-200 plays in the development of the gonads. In Japanese flounder, the two binding sites for the miR-200 family in the 3′UTR of amh were found through bioinformatic prediction. Double luciferase and green fluorescent protein reporter experiments demonstrated amh to be directly targeted by miR-200a and miR-200b. Moreover, miR-200a and miR-200b reduced the expression of amh through site 1 rather than site 2. To explore the regulatory role of miR-200a in gonadal development, we further overexpressed miR-200a in the primary Sertoli cells of the testis. With the overexpression of miR-200a, the expression of amh decreased, while the expression of the other two male sex-related genes, dmrt1 (doublesex and mab-3 related transcription factor 1) and gsdf (diagonal soma driven factor), increased significantly. This result indicates that the miR-200 family regulates the gonadal differentiation and development by targeting amh in Japanese flounder.
      Citation: Fishes
      PubDate: 2022-05-31
      DOI: 10.3390/fishes7030129
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 130: Cloning of Grass Carp Chemokine XC Receptor 1
           (XCR1) Gene and Evaluation of Its Expression in Various Organs after GCRV
           Infection

    • Authors: Hailuo Yu, Yi Liu, Tiaoyi Xiao, Hongquan Wang, Baohong Xu
      First page: 130
      Abstract: Interaction between the chemokine receptor XCR1 and its ligand is closely related to the immune function in animals; however, there are only a few reports on role of XCR1 in the immune system of fish. We aimed to analyze the expression of XCR1 in various organs or tissues of grass carp before and after Grass Carp Reovirus (GCRV) infection to better understand the function of XCR1 in resistance to GCRV infection. We cloned and sequenced the cDNA of grass carp XCR1 and analyzed the molecular structure of XCR1 based its amino acid sequence. Further, we analyzed the relative expression levels of XCR1 in different organs or tissues of male parent grass carp with GCRV resistance (P1) and their first-generation offspring (F1) before and after GCRV infection. Our results show that the total length of cDNA of the grass carp XCR1 gene is 1659 bp and encodes 365 amino acids. XCR1 contains seven conserved transmembrane helical domains. The homologous tertiary structure of XCR1 is similar to its homologs in other species. After artificial GCRV infection, there were significant differences in the expression of the grass carp XCR1 gene in different tissues, at different time points, and between P1 and F1 fish. These results will contribute to our understanding of the role of XCR1 in fish immune responses and contribute to the development of GCRV-resistant grass carp.
      Citation: Fishes
      PubDate: 2022-05-31
      DOI: 10.3390/fishes7030130
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 131: Sub-Saharan Africa Freshwater Fisheries under
           Climate Change: A Review of Impacts, Adaptation, and Mitigation Measures

    • Authors: Rodney Tatenda Muringai, Paramu Mafongoya, Romano Trent Lottering
      First page: 131
      Abstract: Sub-Saharan Africa’s freshwater fisheries contribute significantly to the livelihoods and food security of millions of people within the region. However, freshwater fisheries are experiencing multiple anthropogenic stressors such as overfishing, illegal fishing, pollution, and climate change. There is a substantial body of literature on the effects of climate change on freshwater fisheries in Sub-Saharan Africa. This study reviews the existing literature and highlights the effects of climate change on freshwater fisheries, the adaptation strategies of fishery-dependent households in response to the effects, and fisheries’ management and mitigation efforts in the face of climate change. The general effects of climate change on freshwater environments include warming water temperatures, increased stratification, modified hydrological processes, and increased pollutants. These effects adversely affect the physiological processes of fish and the overall wellbeing of fishery-dependent people. To cope with the effects of fluctuating fishery resources due to climate change, fishery-dependent people have adopted several adaptation strategies including livelihood diversification, changing their fishing gear, increasing their fishing efforts, and targeting new species. Several management attempts have been made to enhance the sustainability of fishery resources, from local to regional levels. This study recommends the participation of the resource users in the formulation of policies aimed at promoting climate change adaptation and the resilience of freshwater fisheries for sustainable development.
      Citation: Fishes
      PubDate: 2022-06-02
      DOI: 10.3390/fishes7030131
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 132: Nutrients and Bioactive Compounds in Seafood:
           Quantitative Literature Research Analysis

    • Authors: Alessandra Durazzo, Gabriella Di Lena, Paolo Gabrielli, Antonello Santini, Ginevra Lombardi-Boccia, Massimo Lucarini
      First page: 132
      Abstract: This perspective presents current and updated advances in research on nutrients and bioactive compounds in seafood. It is based on a literature quantitative research analysis approach. The main features of seafood components are introduced. This perspective aims at providing a current framework that relates nutrients, bioactive compounds, and seafood in a novel integrated and multidisciplinary manner, highlighting the current knowledge, the main research lines, and emerging strategies. The literature search was carried out by means of the Scopus database, and 22,542 documents were retrieved in the period from 1932 to 2024. Particularly, from the perspective of nutrition and health outputs, the main terms correlated with research on the relationship between seafood and nutritional and bioactive components, and the main existing research lines focused on this topic, were identified. The top recurring keywords were human/s, female, diet, nutrition, fish, male, adult, food intake.
      Citation: Fishes
      PubDate: 2022-06-05
      DOI: 10.3390/fishes7030132
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 133: The Use of Cinnamon Essential Oils in
           Aquaculture: Antibacterial, Anesthetic, Growth-Promoting, and Antioxidant
           Effects

    • Authors: Guerino Bandeira Junior, Adriane Erbice Bianchini, Carine de Freitas Souza, Sharine Nunes Descovi, Liana da Silva Fernandes, Lenise de Lima Silva, Juliana Felipetto Cargnelutti, Bernardo Baldisserotto
      First page: 133
      Abstract: Cinnamon essential oils (EOs) are widely known for their pharmaceutical properties; however, studies investigating the use of these EOs in aquaculture are scarce. The aims of this study were to evaluate the anesthetic effect of bathing silver catfish (Rhamdia quelen) with Cinnamomum cassia EO (CCEO) and its nanoemulsion (NCCEO); the growth-promoting and antioxidant effects of dietary supplementation with CCEO in silver catfish; and the in vitro antibacterial effect of CCEO, NCCEO, and Cinnamomum zeylanicum EO (CZEO) against bacteria isolated from diseased silver catfish. The two cinnamon EOs showed promising antibacterial activity, which was potentiated by the nanoemulsion. CCEO showed satisfactory anesthetic activity in silver catfish, and its nanoemulsion intensified the sedative activity. Supplementation of 1.0 mL CCEO per kg of diet for 60 days increased weight, length, and weight gain when compared to the control group, evidencing the growth-promoting activity of this EO. Dietary supplementation of CCEO for 30 and 60 days also showed an antioxidant effect, as it decreased levels of thiobarbituric acid reactive species and increased the superoxide dismutase activity in the liver of silver catfish. Therefore, cinnamon EOs have a promising use in aquaculture.
      Citation: Fishes
      PubDate: 2022-06-06
      DOI: 10.3390/fishes7030133
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 134: Sporosarcina aquimarina MS4 Regulates the
           Digestive Enzyme Activities, Body Wall Nutrients, Gut Microbiota, and
           Metabolites of Apostichopus japonicus

    • Authors: Hong Yi, Qinglu Bai, Ying Li, Honglei Zhan, Yujia Liu, Bingnan Liu, Jihui Wang
      First page: 134
      Abstract: Sporosarcina aquimarina MS4 is a microecological preparation for overwintering Apostichopus japonicus, which has an immune regulation function, but its role in the nutritional regulation of A. japonicus is not clear. This study aimed to describe the effects of S. aquimarina MS4 on the growth, digestion, and body wall nutrition of A. japonicus through feeding experiments and to discuss the potential mechanism of S. aquimarina MS4 regulating gut function through the detection of gut microbiota and metabolites. After 60 days of culture, the growth performance of A. japonicus fed S. aquimarina MS4 (108 cfu/g) significantly improved, and the content of polysaccharide, leucine, phenylalanine, lysine, and docosahexaenoic acid in the body wall significantly increased. Gut microbiota analysis showed that although Proteobacteria, Verrucomicrobia, Firmicutes, and Bacteroidetes were the predominant phyla in all the sea cucumbers, Haloferula and Rubritalea showed significant difference between the group fed with or without S. aquimarina MS4. Metabolomics analysis showed that differential metabolites in the gut were mainly enriched in amino acid metabolism and lipid metabolism. The association analysis of differential metabolites and microbiota showed that the production of some differential metabolites was significantly related to differential microorganisms, which improved the understanding of the function of microorganisms and their roles in the gut of A. japonicus. This study reveals the life activities such as growth and metabolism of A. japonicus, and it provides support for the functional study of the gut microbiome of A. japonicus.
      Citation: Fishes
      PubDate: 2022-06-07
      DOI: 10.3390/fishes7030134
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 135: Regional Population Structure of the European
           Eel at the Southern Limit of Its Distribution Revealed by Otolith Shape
           Signature

    • Authors: Ana Moura, Ester Dias, Rodrigo López, Carlos Antunes
      First page: 135
      Abstract: Given the European eel population’s marked decrease since the 1980s, it has become urgent to collect information describing its regional population structure to improve management plans. The Minho River (NW-Portugal, SW-Europe) is an important basin for the eel at the southern limit of its distribution, but the species is poorly described. Thus, we aimed to study the structure of the European eel population in the Minho River using otolith shape analysis, which has proven to be effective in discriminating fish groups experiencing different environmental conditions through ontogeny. Our results showed complete discrimination between the two main types of habitats studied (tributaries and estuaries). Otoliths of eels from the estuary were rectangular and elliptic, whereas in the tributaries they presented a more round and circular form. Eels collected in both habitats were mostly yellow-stage eels with a similar age range, but the eels from the tributaries showed smaller length-at-age and lower body condition than those collected in the estuary. Additionally, the sex ratio was skewed towards males in the tributaries and females in the estuary. This study reveals that there are at least two distinct groups of eels in this basin, likely with different development characteristics.
      Citation: Fishes
      PubDate: 2022-06-07
      DOI: 10.3390/fishes7030135
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 136: Assessing the Stock Dynamics of Elasmobranchii
           off the Southern Coast of Sicily by Using Trawl Survey Data

    • Authors: Fabio Falsone, Vita Gancitano, Michele Luca Geraci, Giacomo Sardo, Danilo Scannella, Fabrizio Serena, Sergio Vitale, Fabio Fiorentino
      First page: 136
      Abstract: Elasmobranchii (sharks and rays), which have peculiar and vulnerable life-history traits, are highly threatened by fishing activities. Indeed, between 53% and 71% of Mediterranean elasmobranch species are at risk of extinction. In this context, using the abundance MSY (AMSY) model, the present study provides an assessment of 20 batoids and 16 shark species in the Strait of Sicily, sampled during a bottom trawl survey from 1995 to 2020. Overall, the outputs underline a progressively improving condition for shark and ray assemblages of both shelf and eurybathic zones. As for slope-dwelling species, a horseshoe-shaped dynamic, characterized by a progressive decrease in relative harvesting pressure and an increase in relative biomass followed by an increase in fishing pressure and decrease in biomass, was detected. The dynamics of the Elasmobranchii living in the Strait of Sicily appear to be affected by changes in the fishing patterns of trawlers, showing a shift from shallow water to bathyal fishing grounds and targeting deep-water red shrimp. In this context, it seems wise to limit the impact of deep-water fisheries on Elasmobranchii by reducing fishing efforts and implementing ad hoc management measures aimed at safeguarding these vulnerable species.
      Citation: Fishes
      PubDate: 2022-06-07
      DOI: 10.3390/fishes7030136
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 137: Incorporation of Fructooligosaccharides in
           Diets Influence Growth Performance, Digestive Enzyme Activity, and
           Expression of Intestinal Barrier Function Genes in Tropical Gar
           (Atractosteus tropicus) Larvae

    • Authors: Graciela M. Pérez-Jiménez, Emyr Saul Peña-Marín, Claudia I. Maytorena-Verdugo, Cesar Antonio Sepúlveda-Quiroz, Luis Daniel Jiménez-Martínez, Susana De la Rosa-García, Gloria Gertrudys Asencio-Alcudia, Rafael Martínez, Dariel Tovar-Ramírez, Mario A. Galaviz, Talhia Martínez-Burguete, Carlos A. Alvarez-González, Carina Shianya Alvarez-Villagomez
      First page: 137
      Abstract: This study was conducted to investigate the effects of dietary fructooligosaccharides (FOS) on the growth, survival rate, digestive enzyms activity, and the expression of intestinal barrier function genes in tropical gar (Atractosteus tropicus) larvae. A total of 960 larvae (0.030 ± 0.006 g) were fed three diets supplemented with increasing FOS concentrations (2.5, 5, and 7.5 g kg−1) and a control diet for 15 days. Results revealed that a 7.5 g kg−1 FOS supplementation improved weight gain, specific growth rate, and survival rate (p < 0.05). Furthermore, 5 g kg−1 FOS supplementation increased alkaline protease and amylase activities and induced an upregulation of the claudin-17 gene expression (p < 0.05). Meanwhile, the inclusion of 7.5 g kg−1 FOS induced the upregulation of mucin 2 (muc-2), and the tight junction genes zo-2 and claudin-3 (p < 0.05). In addition, 2.5, 5, and 7.5 g kg−1 FOS promoted the downregulation of the claudin-15 gene expression (p < 0.05). At the same time, FOS inclusion did not increase the pro-inflammatory cytokine il-8 expression. We can conclude that 7.5 g kg−1 FOS supplementation improves growth performance, survival rate, and digestive capacity, and could contribute to the reinforcement of the intestinal barrier function of Tropical gar larvae.
      Citation: Fishes
      PubDate: 2022-06-10
      DOI: 10.3390/fishes7030137
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 138: Phosphorus Absorption and Excretion in Hybrid
           Sturgeon (Huso dauricus♀ X Acipenser schrenckii♂) Intubated
           with Different Ca/P Ratios

    • Authors: Jiali Jin, Zhipeng Chu, Rui Ruan, Wei Liu, Xihua Chen, Chuangju Li
      First page: 138
      Abstract: To study the effect of Ca/P ratio on the P and Ca absorption and excretion in hybrid sturgeon (Huso dauricus♀ X Acipenser schrenckii♂), five groups of fish were intubated with 100 mg P·kg−1 BW with the Ca/P ratios of 0:1, 0.25:1, 0.5:1, 1:1, and 2:1. Plasma P concentrations were significantly elevated at Ca/P ratios below 2:1, and the highest value was obtained at Ca/P ratio of 0.5:1. Plasma Ca content was significantly increased at the highest Ca/P ratio. Urine P excretion rate in the fish intubated with Ca/P ratio of 0.5:1 was significantly higher than that of the groups with Ca/P ratios of 0:1 and 2:1. The highest urea excretion rates were observed at Ca/P ratio of 0.5:1 and 1:1. The total P excretion at 48 h post intubation reached about 30 mg·kg−1 BW, which was recorded for the group with Ca/P ratio of 0.5:1. The present study showed that P absorption efficiency was improved in hybrid sturgeon at Ca/P ratio of 0.5:1, indicating that P inclusion level in sturgeon feed can be further optimized to reduce dietary P input and lower the excessive undigested P discharge into the rearing water.
      Citation: Fishes
      PubDate: 2022-06-10
      DOI: 10.3390/fishes7030138
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 139: Molecular Cloning of Heat Shock Protein 60
           (SpHSP60) from Schizothorax prenanti and the Gene Expressions of Four
           SpHSPs during Lipopolysaccharide (LPS) Infection

    • Authors: Jianlu Zhang, Jiqin Huang, Cheng Fang, Wanchun Li, Hu Zhao, Fei Kong, Han Zhang, Hongxing Zhang, Qijun Wang
      First page: 139
      Abstract: Heat shock proteins (HSPs) play a key role in anti-stress and immune processes and are associated with autoimmune diseases. In order to explore the immunological role of HSPs from Schizothorax prenanti (S. prenanti), SpHSP60 was cloned for the first time in this study, and the gene expressions of SpHSP27, SpHSP60, SpHSP70 and SpHSP90 in the hepatopancreas, head kidney, hindgut and spleen were analyzed by quantitative real-time PCR (qPCR) after treatment with lipopolysaccharide (LPS). The open reading frame of the SpHSP60 gene (GenBank accession number ON245159) is 1728 bp. It encodes a protein of 575 amino acids. Its C-terminus is a highly conserved and repeated glycine sequence, which is an important cofactor in ATP binding. Compared with the control group, most of the SpHSPs were significantly upregulated in the tissues examined at 12 or 24 h after LPS challenge. The most abundant expression of SpHSP70 was found in the head kidney at 24 h after LPS injection, followed by SpHSP27 in the spleen at 24 h; both of these SpHSPs displayed strong expression under the LPS stresses, about 20–70 fold more than that of SpHSP60 and SpHSP90. The temporal expression patterns of the four SpHSP genes were different in the four tissues examined. Taken together, the results suggest that SpHSP27, SpHSP60, SpHSP70 and SpHSP90 participate in innate immunity stimulated by LPS, and the response intensity of the SpHSPs was organ-specific, indicating they could provide early warning information against bacterial infection. The findings in our study will contribute to better understanding the biological processes and important roles of SpHSPs involved in defending against pathogenic bacterial challenge.
      Citation: Fishes
      PubDate: 2022-06-13
      DOI: 10.3390/fishes7030139
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 140: Conversion of Fishery Waste to Proteases by
           Streptomyces speibonae and Their Application in Antioxidant Preparation

    • Authors: Thi Ngoc Tran, Chien Thang Doan, Van Bon Nguyen, Anh Dzung Nguyen, San-Lang Wang
      First page: 140
      Abstract: Proteinaceous wastes from the fishery process are an abundant renewable resource for the recovery of a variety of high-value products. This work attempted to utilize several proteinaceous wastes to produce proteases using the Streptomyces speibonae TKU048 strain. Among different possible carbon and nitrogen sources, the protease productive activity of S. speibonae TKU048 was optimal on 1% tuna head powder. Further, the casein/gelatin/tuna head powder zymography of the crude enzyme revealed the presence of three/nine/six proteases, respectively. The crude-enzyme cocktail of S. speibonae TKU048 exhibited the best proteolytic activity at 70 °C and pH = 5.8. Sodium dodecyl sulfate strongly enhanced the proteolytic activity of the cocktail, whereas FeCl3, CuSO4, and ethylenediaminetetraacetic acid could completely inhibit the enzyme activity. Additionally, the crude-enzyme cocktail of S. speibonae TKU048 could efficiently enhance the 2,2-diphenyl-1-picrylhydrazyl and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activities of all tested proteinaceous materials including the head, viscera, and meat of tuna fish; the head, viscera, and meat of tilapia fish; the head, meat, and shell of shrimp; squid pen; crab shell; and soybean. Taken together, S. speibonae TKU048 revealed potential in the reclamation of proteinaceous wastes for protease production and antioxidant preparation.
      Citation: Fishes
      PubDate: 2022-06-14
      DOI: 10.3390/fishes7030140
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 141: Trawl Fishing Fleet Operations Used to
           Illustrate the Life Cycle of the Southern Brown Shrimp: Insights to
           Management and Sustainable Fisheries

    • Authors: Ualerson I. Peixoto, Adauto S. Mello-Filho, Bianca Bentes, Victoria J. Isaac
      First page: 141
      Abstract: The purpose of this study was to better understand the life cycle of brown shrimp along the Amazon Continental Shelf by using spatial and temporal trawl fleet activities. A total of 208,121 specimens and 1281 trawls were studied throughout the course of 13 years of shrimp size composition. To investigate differences in length composition between fishing grounds, months, and depth, a PERMANOVA analysis was employed. A geographic information system was developed for environmental characterisation and spatiotemporal trawl fleet distribution. Our findings show that the industrial trawl shrimp fleet has a close relationship with shrimp biological characteristics, following shrimp migration patterns in different months, locations, and depths during different stages of their life cycle, and that this fleet acts on two-yearly cohorts. The management measures of limiting effort (number of vessels) appear enough to avoid overcapitalisation, but the closed period and a proposed no-take fishing zone appear insufficient for what was originally proposed. Ecosystem-based management strategies should be addressed immediately because they would be far more effective than traditional fishery-based management measures in promoting sustainable fishing.
      Citation: Fishes
      PubDate: 2022-06-17
      DOI: 10.3390/fishes7030141
      Issue No: Vol. 7, No. 3 (2022)
       
  • Fishes, Vol. 7, Pages 63: Early Immune Modulation in European Seabass
           (Dicentrarchus labrax) Juveniles in Response to Betanodavirus Infection

    • Authors: Mariana Vaz, Damiana Pires, Pedro Pires, Marco Simões, Ana Pombo, Paulo Santos, Beatriz do Carmo, Ricardo Passos, Janina Z. Costa, Kim D. Thompson, Teresa Baptista
      First page: 63
      Abstract: The early host–pathogen interaction between European seabass (Dicentrarchus labrax) and Betanodavirus was examined by using juvenile fish infected intramuscularly with RGNNV (red-spotted grouper nervous necrosis virus). The time course selected for sampling (0–144 h post-infection (hpi)) covered the early stages of infection, with hematological, antioxidant and immunological responses examined. Early activation of the host’s immune system was seen in the first few hours post-infection (6 to 9 hpi), as evidenced by an increase in tnfα, cd28 and c3 expression in the head kidney of infected fish. Most hematological parameters that were examined showed significant differences between sampling times, including differences in the number of thrombocytes and various leukocyte populations. The plasma lysozyme concentration decreased significantly over the course of the trial, and most antioxidant parameters examined in the liver showed significant differences over the infection period. At 144 hpi, peak expression of tnfα and il-1β coincided with the appearance of disease symptoms, peak levels of virus in the brain and high levels of fish mortality. The results of the study show the importance of analyzing the early interactions between European seabass and Betanodavirus to establish early indicators of infection to prevent more severe outcomes of the infection from occurring.
      Citation: Fishes
      PubDate: 2022-03-11
      DOI: 10.3390/fishes7020063
      Issue No: Vol. 7, No. 2 (2022)
       
  • Fishes, Vol. 7, Pages 64: Scale Development-Related Genes Identified by
           Transcriptome Analysis

    • Authors: Zhicong Zhang, Fengyu Ji, Shouwen Jiang, Zhichao Wu, Qianghua Xu
      First page: 64
      Abstract: Scales, as key structures of fish skin, play an important role in physiological function. The study of fish scale development mechanisms provides a basis for exploring the molecular-level developmental differences between scaled and non-scaled fishes. In this study, alizarin red staining was used to divide the different stages of zebrafish (Danio rerio) scale development. Four developmental stages, namely stage I (~17 dpf, scales have not started to grow), stage II (~33 dpf, the point at which scales start to grow), stage III (~41 dpf, the period in which the scales almost cover the whole body), and stage IV (~3 mpf, scales cover the whole body), were determined and used for subsequent transcriptome analysis. WGCNA (weighted correlation network analysis) and DEG (differentially expressed gene) analysis were used for screening the key genes. Based on the comparison between stage II and stage I, 54 hub-genes were identified by WGCNA analysis. Key genes including the Scpp family (Scpp7, Scpp6, Scpp5, and Scpp8), the Fgf family (Fgfr1b and Fgfr3), Tcf7, Wnt10b, Runx2b, and Il2rb were identified by DEG analysis, which indicated that these genes played important roles in the key nodes of scale development signal pathways. Combined with this analysis, the TGF-β, Wnt/β-catenin, and FGF signaling pathways were suggested to be the most important signal pathways for scales starting to grow. This study laid a foundation for exploring the scale development mechanism of other fishes. The scale development candidate genes identified in the current study will facilitate functional gene identifications in the future.
      Citation: Fishes
      PubDate: 2022-03-12
      DOI: 10.3390/fishes7020064
      Issue No: Vol. 7, No. 2 (2022)
       
  • Fishes, Vol. 7, Pages 65: Comparative Analysis of Intestinal
           Characteristics of Largemouth Bass (Micropterus salmoides) and Intestinal
           Flora with Different Growth Rates

    • Authors: Xin Su, Da Ji, Junjie Yao, Yuanlong Zou, Mengzhi Yan
      First page: 65
      Abstract: To explore the causes of different growth rates among juvenile populations of largemouth bass, in the present study, a batch of largemouth bass juveniles reared under the same conditions were divided into a fast-growing group and a slow-growing group. We used histological, enzymatic and molecular biology methods to analyze and determine their histomorphological changes, digestive enzyme activity and intestinal floral composition. The fast-growing group had a significantly (p ≤ 0.01) greater intestinal fold height and muscle thickness than the slow-growing group. Lipase activity was significantly (p ≤ 0.01) higher in the fast-growing group than in the slow-growing group. Intestinal microbial analysis showed that the relative abundance of Actinobacteria and Halomonas in the fast-growing group was higher than that in the slow-growing group. This research shows that the differentiation of growth rates in juvenile largemouth bass populations is closely related to intestinal fold status, lipase activity, and intestinal flora.
      Citation: Fishes
      PubDate: 2022-03-15
      DOI: 10.3390/fishes7020065
      Issue No: Vol. 7, No. 2 (2022)
       
  • Fishes, Vol. 7, Pages 66: A Pilot Study Assessing a Concentration of 100
           mg/L Alizarin Complexone (ALC) to Mark Calcified Structures in
           Hypophthalmichthys molitrix

    • Authors: Yahua Zhu, Tao Jiang, Xiubao Chen, Hongbo Liu, Quinton Phelps, Jian Yang
      First page: 66
      Abstract: The effectiveness of chemical compounds for marking hard tissues in juvenile silver carp (Hypophthalmichthys molitrix) is not well known. We analyzed the use of alizarin complexone (ALC) as a fluorescent marker to mark the various hard structures of juvenile silver carp. Experimental fish (~2 months old) were randomly assigned to either control or marking groups, which were immersed in 0 or 100 mg/L ALC solutions, respectively, for 2 days. The otoliths, fin rays, and scales of the fish were then sampled, visualized using fluorescence microscopy, and evaluated after 10 days. The ALC treatment was effective for marking certain hard structures and the marking color was affected by the light source. There were no obvious differences in the marking efficiency of rays from pectoral, dorsal, ventral, anal, and caudal fins, but the lapilli and lateral line scales were marked most effectively from the sampled otolith and scale types, respectively. Our findings indicate that ALC immersion and fin ray and scale sampling can be used for the effective marking and non-lethal evaluation of hard structures in juvenile silver carp.
      Citation: Fishes
      PubDate: 2022-03-16
      DOI: 10.3390/fishes7020066
      Issue No: Vol. 7, No. 2 (2022)
       
  • Fishes, Vol. 7, Pages 67: Sensitivity of Zebrafish Embryogenesis to Risk
           of Fotemustine Exposure

    • Authors: Davide Di Paola, Carmelo Iaria, Giovanni Lanteri, Marika Cordaro, Rosalia Crupi, Rosalba Siracusa, Ramona D’Amico, Roberta Fusco, Daniela Impellizzeri, Salvatore Cuzzocrea, Nunziacarla Spanò, Enrico Gugliandolo, Alessio Filippo Peritore
      First page: 67
      Abstract: Several anthropogenic products in wastewater are considered a threat to the aquatic environment. In addition to common industrial pollutants, levels of pharmaceuticals have been increasingly found in the environment in recent years, which may present a strong risk to the aquatic species that live there. The constant consumption of biologically active chemicals for human health has been matched by an increase in the leaking of these compounds in natural habitats over the last two decades. This study is aimed at evaluating the developmental toxicity of fotemustine in the ecological environment. Zebrafish embryos were exposed to doses of 25, 50 and 100 µg/mL from 4 h post-fertilization to 120 h. This study confirms that fotemustine exposure at 50 and 100 µg/mL affects the survival and hatching rate, morphology score and body length. Additionally, it significantly disturbs the antioxidant defense system and increases ROS in zebrafish larvae. From the molecular point of view, fotemustine exposure strongly induces apoptosis, endoplasmic reticulum stress (ERS) and the Wnt signaling pathway.
      Citation: Fishes
      PubDate: 2022-03-17
      DOI: 10.3390/fishes7020067
      Issue No: Vol. 7, No. 2 (2022)
       
  • Fishes, Vol. 7, Pages 68: Age, Growth, and Utility of Otolith
           Morphometrics as Predictors of Age in the European Barracuda, Sphyraena
           sphyraena (Sphyraenidae): Preliminary Data

    • Authors: Josipa Ferri, Anđela Brzica
      First page: 68
      Abstract: Age and growth of the European barracuda, Sphyraena sphyraena, were determined by examining sagittal otoliths belonging to fish sampled in the eastern Adriatic Sea, as the northernmost region of the Mediterranean. A total of 113 specimens (59 females, 53 males, and one individual of indeterminate sex), ranging from 23.4 to 42.5 cm in total length, were analyzed. The maximum observed age was 5 years for both females and males, and this barracuda population was dominated by 3 year old fish. Growth was described by the von Bertalanffy growth curve (L∞ = 55.58 cm, K = 0.12 year−1, t0 = −4.29 year, R2 = 0.580), and the growth performance index (Φ’) was 2.57. Otolith length, width, and mass were measured, and the utility of these morphometrics as predictors of age in S. sphyraena was evaluated. The results showed that counting otolith annuli produced a better estimation of age than proposed linear models based on relationships between observed fish age and otolith morphometrics. In comparison with age and growth data available in the literature for S. sphyraena, our results from the Adriatic Sea provide more insights into the life-history traits of this species and can be used in the future effective management and conservation.
      Citation: Fishes
      PubDate: 2022-03-17
      DOI: 10.3390/fishes7020068
      Issue No: Vol. 7, No. 2 (2022)
       
  • Fishes, Vol. 7, Pages 69: Molecular Characterization of Aquaporins Genes
           from the Razor Clam Sinonovacula constricta and Their Potential Role in
           Salinity Tolerance

    • Authors: Wenbin Ruan, Yinghui Dong, Zhihua Lin, Lin He
      First page: 69
      Abstract: Aquaporins (AQPs) play crucial roles in osmoregulation, but the knowledge about the functions of AQPs in Sinonovacula constricta is unclear. In this study, Sc-AQP1, Sc-AQP8, and Sc-AQP11 were identified from S. constricta, and the three Sc-AQPs are highly conserved compared to the known AQPs. The qRT-PCR analysis revealed that the highest mRNA expressions of Sc-AQP1, Sc-AQP8, and Sc-AQP11 were detected in the gill, digestive gland, and adductor muscle, respectively. In addition, the highest mRNA expression of Sc-AQP1 and Sc-AQP11 was detected in the D-shaped larvae stage, whereas that of SC-AQP8 was observed in the umbo larvae stage. The mRNA expression of Sc-AQP1, Sc-AQP8, and Sc-AQP11 significantly increased to 12.45-, 12.36-, and 27.44-folds post-exposure of low salinity (3.5 psu), while only Sc-AQP1 and Sc-AQP11 significantly increased post-exposure of high salinity (35 psu) (p < 0.01). The fluorescence in situ hybridization also showed that the salinity shift led to the boost of Sc-AQP1, Sc-AQP8, and Sc-AQP11 mRNA expression in gill filament, digestive gland, and adductor muscle, respectively. Knockdown of the Sc-AQP1 and Sc-AQP8 led to the decreased osmotic pressure in the hemolymph. Overall, these findings would contribute to the comprehension of the osmoregulation pattern of AQPs in S. constricta.
      Citation: Fishes
      PubDate: 2022-03-18
      DOI: 10.3390/fishes7020069
      Issue No: Vol. 7, No. 2 (2022)
       
  • Fishes, Vol. 7, Pages 70: A Comparison of eDNA and Visual Survey Methods
           for Detection of Longnose Darter Percina nasuta in Missouri

    • Authors: Jacob T. Westhoff, Leah K. Berkman, Katy E. Klymus, Nathan L. Thompson, Catherine A. Richter
      First page: 70
      Abstract: The longnose darter Percina nasuta is a rare and cryptic fish that recently disappeared from much of its historic range. We developed and used an environmental DNA (eDNA) assay for longnose darter paired with visual surveys to better determine the species’ range and compare detection probability between sampling approaches in an occupancy modeling framework. We detected longnose darter eDNA further upstream in the mainstem St. Francis River than previously reported and in a tributary for the first time. Our multi-scale occupancy approach compared models where detection was constant against a model that allowed detection to vary by survey method. The constant model received the most support indicating survey method was not a strong predictor and detection was estimated at 0.70 (0.45–0.86; 95% CI) across both methods. Our study produced effective longnose darter eDNA primers and demonstrated the application of eDNA for sampling small-bodied, cryptic fish. We detected longnose darter eDNA 27 km upstream of their known range and determined that snorkel surveys are the most efficient sampling method if water clarity allows. We recommend target sample sizes to achieve various detection goals for both sample methods and our results inform future design of distributional and monitoring efforts.
      Citation: Fishes
      PubDate: 2022-03-18
      DOI: 10.3390/fishes7020070
      Issue No: Vol. 7, No. 2 (2022)
       
  • Fishes, Vol. 7, Pages 71: Automatic Fish Age Determination across
           Different Otolith Image Labs Using Domain Adaptation

    • Authors: Alba Ordoñez, Line Eikvil, Arnt-Børre Salberg, Alf Harbitz, Bjarki Þór Elvarsson
      First page: 71
      Abstract: The age determination of fish is fundamental to marine resource management. This task is commonly done by analysis of otoliths performed manually by human experts. Otolith images from Greenland halibut acquired by the Institute of Marine Research (Norway) were recently used to train a convolutional neural network (CNN) for automatically predicting fish age, opening the way for requiring less human effort and availability of expertise by means of deep learning (DL). In this study, we demonstrate that applying a CNN model trained on images from one lab (in Norway) does not lead to a suitable performance when predicting fish ages from otolith images from another lab (in Iceland) for the same species. This is due to a problem known as dataset shift, where the source data, i.e., the dataset the model was trained on have different characteristics from the dataset at test stage, here denoted as target data. We further demonstrate that we can handle this problem by using domain adaptation, such that an existing model trained in the source domain is adapted to perform well in the target domain, without requiring extra annotation effort. We investigate four different approaches: (i) simple adaptation via image standardization, (ii) adversarial generative adaptation, (iii) adversarial discriminative adaptation and (iv) self-supervised adaptation. The results show that the performance varies substantially between the methods, with adversarial discriminative and self-supervised adaptations being the best approaches. Without using a domain adaptation approach, the root mean squared error (RMSE) and coefficient of variation (CV) on the Icelandic dataset are as high as 5.12 years and 28.6%, respectively, whereas by using the self-supervised domain adaptation, the RMSE and CV are reduced to 1.94 years and 11.1%. We conclude that careful consideration must be given before DL-based predictors are applied to perform large scale inference. Despite that, domain adaptation is a promising solution for handling problems of dataset shift across image labs.
      Citation: Fishes
      PubDate: 2022-03-18
      DOI: 10.3390/fishes7020071
      Issue No: Vol. 7, No. 2 (2022)
       
  • Fishes, Vol. 7, Pages 72: Isolation of Chromatophores from Brown Trout
           (Salmo trutta) Skin

    • Authors: Gašper Renko, Ida Djurdjevič, Simona Sušnik Bajec
      First page: 72
      Abstract: As new techniques for single-cell analysis are evolving, there is a growing need for streamlined and flexible protocols for single-cell suspension preparation and single-cell isolation. Based on previous research on the model species zebrafish (Danio rerio), a novel protocol for the isolation of chromatophores from brown trout (Salmo trutta) skin was developed and specific gene expression in chromatophore types evaluated with qPCR. This is the first report on a protocol for the isolation of chromatophores from the skin of salmonids. The method is simple and fast (taking about 90 min), requires no special equipment and is in line with the high ethical standards required in animal research, as no animals need to be sacrificed. In addition, skin biopsies can be taken from the same fish at multiple time points, allowing monitoring of chromatophore differentiation and their involvement in the formation of pigmentation patterns. The protocol should be effective for the vast majority of salmonid species due to similarities in skin morphology.
      Citation: Fishes
      PubDate: 2022-03-18
      DOI: 10.3390/fishes7020072
      Issue No: Vol. 7, No. 2 (2022)
       
  • Fishes, Vol. 7, Pages 73: Growth Rates of Non-Native Bighead and Silver
           Carp in the Upper Mississippi River

    • Authors: Cortney Lynn Broaddus, James T. Lamer
      First page: 73
      Abstract: Fish age and growth analyses can be used to infer spawning success, recruitment, and population age structure. Understanding these dynamics is important when assessing the impacts of invasive species, such as bighead carp, Hypophthalmichthys nobilis, and silver carp, H. molitrix, (bigheaded carp). These species have established throughout much of the Mississippi River Basin; however, Lock and Dam 19 (LD19) has slowed their establishment in the Upper Mississippi River, resulting in low-density populations with limited reproduction upstream. The age and growth of Bigheaded Carp in recently established populations, especially in this region, are poorly characterized. Therefore, we compared the age and growth of bigheaded carp for four low-density navigation pools of the Mississippi River near the invasion front with one long-established high-density population, separated by LD19. To assess growth rates and age at maturity, we estimated consensus age from pectoral spines, postcleithra, and vertebrae from 1229 bigheaded carp, 30 fish per 50 mm size class. Length at age of capture and back-calculated length-at-age were used to create growth curves using VBGC analysis. The analysis indicated higher growth rates of bighead carp and silver carp upstream of Lock and Dam 19 than downstream. Comparison of growth models with a likelihood ratio test indicated differences in length at time zero between the pools for bighead carp but not for silver carp. However, maximum length and growth rates were significantly different for silver carp upstream and downstream of the dam but not for bighead carp. These results will be used to better understand the population dynamics of this emerging population to inform control and containment actions.
      Citation: Fishes
      PubDate: 2022-03-24
      DOI: 10.3390/fishes7020073
      Issue No: Vol. 7, No. 2 (2022)
       
  • Fishes, Vol. 7, Pages 74: Immunohistochemical Detection of Various
           Proteoglycans in the Extracellular Matrix of Zebra Mussels

    • Authors: Wenkai Wu, Juergen Geist, Sebastian Beggel, Christoph Schmitz, Stefan Milz, Katharina Sternecker
      First page: 74
      Abstract: Mussels have been used as animal models for studying ecotoxicology, biomineralization, and bio-adhesion for many years. Despite a wealth of studies on their shell matrix and byssus proteins, few studies have focused on the extracellular matrix molecules in mussel soft tissues. Extracellular matrix molecules may play important roles in biomineralization, immune reaction, and tissue homeostasis. In the present study, extracellular matrix and mineralization-related molecules in zebra mussel soft tissue were immunolocalized using well-characterized monoclonal antibodies. Our results demonstrate specific immunolocalization for collagen IV, fibronectin, and keratan sulfate in hemocytes; collagen IV in peripheral nerves; and aggrecan, link protein, and collagen XVIII in foot tissue. Laminin, decorin, and osteonectin were also broadly immunolocalized in mussel soft tissues. The distributions of these extracellular matrix molecules in mussel tissues are in line with the cell-mediated shell mineralization hypothesis, providing evidence for the molecules involved in the peripheral nervous system and byssus formation, and explaining the conservation of extracellular matrix molecules during evolution. These results further contribute to establishing zebra mussels as an attractive animal model in biomedical research.
      Citation: Fishes
      PubDate: 2022-03-24
      DOI: 10.3390/fishes7020074
      Issue No: Vol. 7, No. 2 (2022)
       
  • Fishes, Vol. 7, Pages 75: Effects of Social Hierarchy Establishment on
           Stress Response and Cell Phagocytosis in Gilt-Head Sea Bream (Sparus
           aurata)

    • Authors: Mariano Dara, Maria Dioguardi, Mirella Vazzana, Irene Vazzana, Davide Accardi, Pierluigi Carbonara, Sébastien Alfonso, Matteo Cammarata
      First page: 75
      Abstract: Social stress can affect the ability of fish to respond to various stressors, such as pathogens or environmental variations. In this paper, the effects of social stress on gilt-head bream (Sparus aurata) were investigated. To study the effects of physiological stress, we evaluated biochemical and cellular parameters, such as cortisol, glucose, lactate, osmolarity, and phagocytosis, 24 h after the establishment of social hierarchy in a group of three fish. Social hierarchy was determined and characterized by behavioral observation (aggressive acts and feeding order) of the specimens (dominant: “α”; subordinate: “β” and “γ”). After the establishment of social hierarchy, we observed that, overall, levels of plasma cortisol and other biochemical plasmatic stress markers (glucose and lactate) were higher in subordinate individuals than in dominant individuals. In addition, the modulation of phagocytic activity of the peritoneal exudate cells (PECs) demonstrated that social stress appeared to affect immune response. Finally, principal component analysis clearly separated the subordinate fish groups from the dominant groups, based on stress markers and the phagocytic activity of peritoneal exudate cells. This study contributes to current knowledge on gilt-head sea bream, helping to understand the link between social stress, behavior, and physiology of this species, relevant in the aquaculture sector, where fish are subjected to several kinds of stress.
      Citation: Fishes
      PubDate: 2022-03-28
      DOI: 10.3390/fishes7020075
      Issue No: Vol. 7, No. 2 (2022)
       
  • Fishes, Vol. 7, Pages 76: Scientific Research and Its Influence in
           Decision-Making of Tuna Regional Fisheries Management Organizations: Case
           Studies in the Atlantic Ocean and Indian Ocean

    • Authors: Shih-Ming Kao, Huan-Sheng Tseng
      First page: 76
      Abstract: Scientific research has played an important role in the conservation and management of high seas fisheries resources since the adoption and entry into the force of the 1982 United Nations Convention on the Law of the Sea (UNCLOS). In addition, regional fisheries management organizations (RFMOs) have become the most important platform in addressing fisheries-related issues under the contemporary international fisheries legal regime, which also includes the responsibility to ensure that their decisions have to properly incorporate recommendations of scientific research into their decisions. This paper aims to analyze, from a legal aspect, how scientific research plays its role in the formation and adoption of conservation and management measures (CMMs) in RFMOs and finds that scientific research has become an essential and integral part of both International Commission on the Conservation of Atlantic Tunas (ICCAT) and the Indian Ocean Tuna Commission (IOTC). Although, on some occasions, these recommendations will not be totally accepted and adopted by the Commission due to social, economic, and political considerations, the results from scientific research have become the basis for issues related to conservation and management measures discussed in RFMOs and will be more influential if the Scientific Committee provides a more concrete recommendation to the Commission.
      Citation: Fishes
      PubDate: 2022-03-28
      DOI: 10.3390/fishes7020076
      Issue No: Vol. 7, No. 2 (2022)
       
  • Fishes, Vol. 7, Pages 77: Length–Weight Relationships and Growth
           Parameters of Common and Leafy Seadragons (Syngnathidae) from a Public
           Aquarium

    • Authors: Daniel Pauly, Leslee Matsushige, Janet Malacane, Amanda Hay, Elaine Chu, Melanie Warren
      First page: 77
      Abstract: The length–weight relationships (LWR) of the common seadragon Phyllopteryx taeniolatus (Lacepède, 1804) and the leafy seadragon Phycodurus eques (Günther, 1865), Syngnathidae, are presented in this paper, based on specimens raised in the Birch Aquarium at Scripps, La Jolla, California. Furthermore, we used the length at known age of 40 specimens of common and 15 leafy seadragons to estimate the parameter of the von Bertalanffy growth function (VBGF) for these species. Some of the pros and cons of the newly proposed length type used, ‘scalene length’ are presented. The parameters of the LWR and the VBGF parameters are discussed, with an emphasis on the rearing conditions, the peculiar anatomy of seadragons, especially of P. eques, and on the Gill-Oxygen Limitation Theory (GOLT).
      Citation: Fishes
      PubDate: 2022-03-31
      DOI: 10.3390/fishes7020077
      Issue No: Vol. 7, No. 2 (2022)
       
  • Fishes, Vol. 7, Pages 78: Hydroxytyrosol Attenuates High-Fat-Diet-Induced
           Oxidative Stress, Apoptosis and Inflammation of Blunt Snout Bream
           (Megalobrama amblycephala) through Its Regulation of Mitochondrial
           Homeostasis

    • Authors: Yanzou Dong, Tian Xia, Manhan Yu, Ling Wang, Kai Song, Chunxiao Zhang, Kangle Lu
      First page: 78
      Abstract: The present study was conducted to investigate the effects of dietary hydroxytyrosol (HT) on oxidative stress, inflammation and mitochondrial homeostasis in blunt snout bream (Megalobrama amblycephala). Fish were fed a low-fat diet (LFD, 5% lipid), a high-fat diet (HFD, 15% lipid), an LFD supplementing 200 mg/kg HT, or an HFD supplementing 200 mg/kg HT. After 10-week feeding, significant reduction of growth was observed in fish fed HFD, compared with other groups. HFD caused oxidative stress and more apoptosis of hepatocytes, while HT addition resulted in significant decrease of ROS and MDA contents, and the apoptotic hepatocytes. Moreover, the expression of genes involving inflammation of HFD group were elevated. Supplementing HT to HFD can attenuate this. All the activities of complexes of mitochondria in the HFD group were decreased compared with those in the LFD group, while supplementing HT to HFD significantly increased complex I-III activities. Furthermore, HFD downregulated the expressions of Atg5 and NRF-1 which induced the failure of mitophagy and biogenesis, while, supplementing HT to HFD reversed these expressions involving mitochondrial autophagy and biogenesis. In summary, adding HT to HFD relieved oxidative stress, apoptosis and inflammation, likely due to its regulation of mitochondrial homeostasis.
      Citation: Fishes
      PubDate: 2022-03-31
      DOI: 10.3390/fishes7020078
      Issue No: Vol. 7, No. 2 (2022)
       
  • Fishes, Vol. 7, Pages 79: Transcriptome Analysis of Immune Responses and
           Metabolic Regulations of Chinese Soft-Shelled Turtle (Pelodiscus sinensis)
           against Edwardsiella tarda Infection

    • Authors: Qianrong Liang, Ningyu Zhu, Xiaoye Zheng, Xueyan Ding, Runzhen He, Hongsen Xu, Feifei Cao, Huili Xue, Fan Zhou, Tianlun Zheng
      First page: 79
      Abstract: The Chinese soft-shelled turtle (Pelodiscus sinensis) is an important aquatic species in southern China that is threatened by many serious diseases. Edwardsiella tarda is one of the highly pathogenic bacteria that cause the white abdominal shell disease. Yet, little is known about the immune and metabolic responses of the Chinese soft-shelled turtle against E. tarda infection. In the paper, gene expression profiles in the turtle liver were obtained to study the immune responses and metabolic regulations induced by E. tarda infection using RNA sequencing. A total of 3908 differentially expressed unigenes between the experimental group and the control group were obtained by transcriptome analysis, among them, were the significantly upregulated unigenes and downregulated unigenes 2065 and 1922, respectively. Further annotation and analysis revealed that the DEGs were mainly enriched in complement and coagulation cascades, phagosome, and steroid hormone biosynthesis pathways, indicating that they were mainly associated with defense mechanisms in the turtle liver against E. tarda four days post infection. For the first time, we reported on the gene profile of anti-E. tarda response in the soft-shelled turtle, and our research might provide valuable data to support further study on anti-E. tarda defense mechanisms in turtles.
      Citation: Fishes
      PubDate: 2022-03-31
      DOI: 10.3390/fishes7020079
      Issue No: Vol. 7, No. 2 (2022)
       
  • Fishes, Vol. 7, Pages 80: Consumption of Non-Native Bigheaded Carps by
           Native Blue Catfish in an Impounded Bay of the Upper Mississippi River

    • Authors: Tad Locher, Jun Wang, Toby Holda, James Lamer
      First page: 80
      Abstract: Adult bigheaded carps Hypophthalmichthys spp. have never been observed in the diets of native fishes in the Mississippi River Basin. In addition, blue catfish Ictalurus furcatus diet preference and foraging behavior have never been studied in the presence of non-native bigheaded carps in the Mississippi River system. We examined the gut contents of adult blue catfish (567–1020 mm, n = 65), captured from a Mississippi River backwater using trammel nets. All items in diets were separated and enumerated, and all fish-like diet items were genetically identified to confirm species-level ID. Bigheaded carp ages were determined by sectioning hard structures (pectoral spines, post-cleithra, and vertebrae). Adult silver carp Hypophthalmichthys molitrix (age 3–5, mean = 3.9 years, SE = 0.2; n = 21) had the highest frequency of occurrence (70%) and constituted the greatest percentage by number (58%) and weight (60%) in/of blue catfish diets. Gizzard shad Dorosoma cepedianum ranked second by all three measures (34%, 25%, and 26%). Finally, 50% to 100% of probable age-based sizes of silver carp exceeded gape measurements of blue catfish, suggesting scavenging was the dominant means of predation. More intensive sampling efforts are required to determine the system-wide importance of bigheaded carp in blue catfish diets.
      Citation: Fishes
      PubDate: 2022-04-01
      DOI: 10.3390/fishes7020080
      Issue No: Vol. 7, No. 2 (2022)
       
  • Fishes, Vol. 7, Pages 81: Maritime Dispute Settlement Law towards
           Sustainable Fishery Governance: The Politics over Marine Spaces vs.
           Audacity of Applicable International Law

    • Authors: M Jahanzeb Butt, Khadija Zulfiqar, Yen-Chiang Chang, Ali M. A. Iqtaish
      First page: 81
      Abstract: The present article discusses and analyses the role and contribution of International Maritime Dispute Settlement Bodies in sustainable fishery governance. From a maritime dispute settlement perspective, the discussion on preserving marine biodiversity, including fisheries and ecosystems, is unprecedented. However, dispute settlement impacts on marine biodiversity require serious attention from the viewpoint of effective implementation of the United Nations Fish Stocks Agreement, International Environmental Law, and United Nations Convention on Law of the Sea. ‘Applicable law’ as primary contention, which could be utilised to preserve marine biodiversity, is preferably employed for ‘ship release’ and ‘delimitation’ issues under dispute settlement mechanisms. Perhaps, the political and legal obstacles in interpreting the ‘law of the sea’ are one area of critique, and the optional dispute settlement mechanism is another. All these significant issues are discussed to develop a rational approach utilising ‘applicable law’ to preserve marine biodiversity and develop sustainable fishery governance. The result will certainly help build a better understanding of the ‘applicable law’ jurisdiction that may be utilised to ensure the sustainability of marine biodiversity.
      Citation: Fishes
      PubDate: 2022-04-02
      DOI: 10.3390/fishes7020081
      Issue No: Vol. 7, No. 2 (2022)
       
  • Fishes, Vol. 7, Pages 82: Developmental Temperature Shapes the Otolith
           Morphology of Metamorphosing and Juvenile Gilthead Seabream (Sparus aurata
           Linnaeus, 1758)

    • Authors: George Geladakis, Chara Kourkouta, Stylianos Somarakis, George Koumoundouros
      First page: 82
      Abstract: Otolith morphological variability is used as a reliable indicator to discriminate fish that experience different environmental conditions during their lifetimes. The present study examined the effects of developmental temperature (DT) during the egg and yolk-sac larval period on the otolith shape and asymmetry of Gilthead seabream in the later metamorphosis (56–58 days post-hatching, dph) and the early juvenile stage (93–95 dph). The experimental populations were reared at different water temperatures (17, 20, or 23 °C DT) from epiboly onset to the end of the yolk-sac larval stage (5–7 days post-fertilization, dpf) and then at a common rearing temperature (20 °C), up to the end of the trials (93–95 dph). Otolith shape and bilateral asymmetry were analyzed at metamorphosis (20–21 mm standard length, SL) and the early juvenile stage (31–32 mm SL). The results of elliptic Fourier analysis showed that DT significantly affected the otolith shape at both stages examined. Furthermore, elevated DT significantly increased the asymmetry levels of seabream otoliths in the early juvenile stage. The results are discussed in terms of the thermally induced long-term changes of seabream otolith morphology and the potential effects of the raised otolith asymmetry on wild seabream juveniles.
      Citation: Fishes
      PubDate: 2022-04-05
      DOI: 10.3390/fishes7020082
      Issue No: Vol. 7, No. 2 (2022)
       
  • Fishes, Vol. 7, Pages 83: Effects of Non-Heated and Heat Processed Krill
           and Squid Meal-Based Diet on Growth Performance and Biochemical
           Composition in Juvenile Pacific Bluefin Tuna Thunnus orientalis

    • Authors: Jeong-Hyeon Cho, Takayuki Kurimoto, Yutaka Haga, Yuji Kamimura, Akira Itoh, Shuichi Satoh
      First page: 83
      Abstract: This study investigated the effects of krill and squid meal and their heat processing on the growth performance and biochemical composition of juvenile Pacific bluefin tuna (PBT) Thunnus orientalis. An experiment using a 2 × 2 factorial design examined the effects of two dietary protein sources (squid and krill meal) and heat treatment (heated and non-heated). Prey fish were provided to a reference group. Fish with an initial mean weight of 74.1 mg were fed one of the five diets. After six days of the feeding trial, the fish fed with krill meal and non-heated diets showed improved growth compared to those fed with the squid meal and heated diets. Fish fed the non-heated diets showed significantly higher whole-body crude protein and crude lipid contents than fish fed the heated diets. These results suggest that nutrient availability could be improved by using krill meal and the non-heated treatment to improve the growth performance of juvenile PBT.
      Citation: Fishes
      PubDate: 2022-04-05
      DOI: 10.3390/fishes7020083
      Issue No: Vol. 7, No. 2 (2022)
       
  • Fishes, Vol. 7, Pages 84: Sustainable Utilization of Fishery Waste in
           

    • Authors: Mohammad Mojibul Hoque Mozumder, Mohammad Muslem Uddin, Petra Schneider, MD Hadiul Islam Raiyan, Most. Gulnaher Akhter Trisha, Tabassum Hossain Tahsin, Subeda Newase
      First page: 84
      Abstract: Living marine resources are limited; therefore, utilizing them sustainably is essential. Not all resources obtained from the sea are used adequately, causing discards, on-board waste, and by-products and waste on land. Recognition of the limited marine resources and increasing environmental pollution has emphasized the need for better utilization of by-products. Waste may include particles of flesh, skin, bones, entrails, shells or liquid stick water. Unfortunately, no fishery waste and by-product management initiatives or projects exist in Bangladesh; by-products are generally thrown into dustbins, ponds, rivers, and the sea. Bangladesh’s fish-processing waste and fishery by-products could be exported, providing a source of foreign currency earnings. Primary and secondary data were collected through documentary analysis, a literature review, and in-depth interviews (n = 129) with fishers and other relevant stakeholders regarding the challenges of Bangladesh’s sustainable fishery by-products and fish-processing waste. The data were analyzed thematically, guided by the most meaningful stories, and show that fish waste, or fishery by-products, should not be considered less valuable than the fish itself but is a precious and profitable resource capable of bringing health, social, economic, and environmental benefits. Our results reveal that fishery waste can expand local communities’, especially fishers’ and other workers’, potential for jobs or alternative income-generating tasks during fishing ban seasons. Finally, suggestions for managing fishery waste and fishery by-products are made to ensure improved and sustainable utilization via a circular bioeconomy.
      Citation: Fishes
      PubDate: 2022-04-06
      DOI: 10.3390/fishes7020084
      Issue No: Vol. 7, No. 2 (2022)
       
  • Fishes, Vol. 7, Pages 85: Assessing the Speciation of Lutjanus campechanus
           and Lutjanus purpureus through Otolith Shape and Genetic Analyses

    • Authors: Angel Marval-Rodríguez, Ximena Renán, Gabriela Galindo-Cortes, Saraí Acuña-Ramírez, María de Lourdes Jiménez-Badillo, Hectorina Rodulfo, Jorge L. Montero-Muñoz, Thierry Brulé, Marcos De Donato
      First page: 85
      Abstract: Based on their morphological and genetic similarity, several studies have proposed that Lutjanus campechanus and Lutjanus purpureus are the same species, but there is no confirmed consensus yet. A population-based study concerning otolith shape and genetic analyses was used to evaluate if L. campechanus and L. purpureus are the same species. Samples were collected from populations in the southwestern Gulf of Mexico and the Venezuelan Caribbean. Otolith shape was evaluated by traditional and outline-based geometric morphometrics. Genetic characterization was performed by sequencing the mtDNA control region and intron 8 of the nuclear gene FASD2. The otolith shape analysis did not indicate differences between species. A nested PERMANOVA identified differences in otolith shape for the nested population factor (fishing area) in morphometrics and shape indexes (p = 0.001) and otolith contour (WLT4 anterior zone, p = 0.005 and WLT4 posterodorsal zone, p = 0.002). An AMOVA found the genetic variation between geographic regions to be 10%, while intrapopulation variation was 90%. Network analysis identified an important connection between haplotypes from different regions. A phylogenetic analysis identified a monophyletic group formed by L. campechanus and L. purpureus, suggesting insufficient evolutionary distances between them. Both otolith shape and molecular analyses identified differences, not between the L. campechanus and L. purpureus species, but among their populations, suggesting that western Atlantic red snappers are experiencing a speciation process.
      Citation: Fishes
      PubDate: 2022-04-07
      DOI: 10.3390/fishes7020085
      Issue No: Vol. 7, No. 2 (2022)
       
  • Fishes, Vol. 7, Pages 86: Applying Acoustic Scattering Layer Descriptors
           to Depict Mid-Trophic Pelagic Organisation: The Case of Atlantic African
           Large Marine Ecosystems Continental Shelf

    • Authors: Anne Mouget, Patrice Brehmer, Yannick Perrot, Uatjavi Uanivi, Ndague Diogoul, Salahedine El Ayoubi, Mohamed Ahmed Jeyid, Abdoulaye Sarré, Nolwenn Béhagle, Aka Marcel Kouassi, Eric Feunteun
      First page: 86
      Abstract: To identify key nonspecific organisational characteristics of the mid-trophic pelagic communities, which remain a challenge, we work with sound scattering layers (SSLs). Application was tested in the three African Atlantic Large Marine Ecosystems (AALMEs) to assess the utility of adapting and developing new acoustic variables. Our methodology allowed comparison between Large Marine Ecosystems (LMEs) based on 14 morphological, spatial and acoustic variables to characterize SSLs over time. These original variables were effective in monitoring and comparing the LMEs, and even allowed us to discriminate different organisations inside the Canary Current LME. Common traits identified for all AALMEs included the importance of the shallowest SSL. However, we identified an unexpected night-time pattern in SSL distributions in the Benguela Current LME which reflect a major difference in diel vertical migration mechanisms relative to other AALMEs. We also highlighted the predominance of elementary sampling unit (ESUs) with a single SSL and an unoccupied tiny layer close to the bottom, even if some ESUs presented up to six SSLs. Inter-annual changes in SSL organisation are highlighted by adaptation of original variables as the proportion of the water column occupied by SSLs and the relative importance of the shallowest SSL. SSL variables have been used mostly in deep water; here, we applied them on the continental shelf. SSL variables can be used to standardize the monitoring of marine ecosystems and capture change in spatial structure and function of mid-trophic pelagic marine ecosystems worldwide, even in data-poor areas where species identification of lower-trophic pelagic organism remains a challenge.
      Citation: Fishes
      PubDate: 2022-04-08
      DOI: 10.3390/fishes7020086
      Issue No: Vol. 7, No. 2 (2022)
       
  • Fishes, Vol. 7, Pages 87: Current Advances and Challenges in Fisheries and
           Aquaculture Science

    • Authors: Eric Hallerman, Maria Angeles Esteban, Bernardo Baldisserotto
      First page: 87
      Abstract: Advances in fisheries and aquaculture science often follow the introduction of new tools or analytic methods [...]
      Citation: Fishes
      PubDate: 2022-04-08
      DOI: 10.3390/fishes7020087
      Issue No: Vol. 7, No. 2 (2022)
       
  • Fishes, Vol. 7, Pages 88: Juvenile Hake Merluccius gayi Spatiotemporal
           Expansion and Adult-Juvenile Relationships in Chile

    • Authors: Daniela V. Yepsen, Luis A. Cubillos, Hugo Arancibia
      First page: 88
      Abstract: The abundance of juvenile fish changes due to endogenous processes, and determining the functional relationships among conspecifics is essential for fisheries’ management. The hake (Merluccius gayi) is an overexploited demersal fish widely distributed in Chile, from 23°39′ S to 47°00′ S in shallow and deep water over the continental shelf and shelf break. We studied the spatiotemporal distribution of hake juveniles (from ages 0 and 1), emphasizing endogenous relationships among juveniles and adults. The abundance per age data were obtained from bottom trawl cruises carried out in the austral winter between 1997 and 2018. Generalized additive models showed a similar spatiotemporal pattern for ages between 0 and 1, and negative effects of adult hake aged seven and older on the abundance of the young generation. Regarding the changes in juvenile abundance, the residual deviance of selected models explained 75.9% (for the age 0) and 95.3% (for the age 1) of the null deviance, revealing a significant increase in juvenile abundance from 2002 to 2007 and subsequent abundance stability at higher levels. Furthermore, the expansion in the abundance of juveniles after 2002 was favored by the low abundance of older adult hake, most which are able to cannibalize young hake. Our results highlight the importance of endogenous factors in the spatial distribution of Chilean hake juveniles to identify nurseries or juvenile areas free of potential cannibal adults.
      Citation: Fishes
      PubDate: 2022-04-12
      DOI: 10.3390/fishes7020088
      Issue No: Vol. 7, No. 2 (2022)
       
  • Fishes, Vol. 7, Pages 89: Changes in Serum Blood Parameters in Farmed
           Rainbow Trout (Oncorhynchus mykiss) Fed with Diets Supplemented with Waste
           Derived from Supercritical Fluid Extraction of Sweet Basil (Ocimum
           basilicum)

    • Authors: Paolo Pastorino, Stefania Bergagna, Cristina Vercelli, Giulia Pagliasso, Lucrezia Dellepiane, Monia Renzi, Raffaella Barbero, Giovanni Re, Antonia Concetta Elia, Alessandro Dondo, Damià Barceló, Marino Prearo
      First page: 89
      Abstract: The antimicrobial and immunostimulant proprieties of aromatic plant extracts have been widely described, but their effects on serum blood biochemistry in fish have not. For this study, we assessed the changes in serum blood biochemical parameters in rainbow trout fed with a fish diet supplemented with a basil supercritical extract (F1-BEO). Our hypothesis was that treatment and time would be associated with changes in 10 serum blood biochemical parameters. F1-BEO was added to a commercial feed (0.5, 1, 2, 3% w/w). The fish were fed for 30 days, and the blood samples were collected at 2 time points (15 and 30 days). A two-way ANOVA showed a significant effect of treatment, time, and interaction treatment × time on creatinine, urea, total protein, albumin, magnesium, and phosphorus (p < 0.05), a significant effect of both time and interaction treatment × time on cholesterol (CHOL), glutamic oxaloacetic transaminase (GOT), and glutamic pyruvic transaminase (GPT) levels, and a significant effect of time on triglycerides (p < 0.05). While changes in several of the parameters were observed, the levels remained within the normal range for rainbow trout. Notably, after 30 days there was a significant decrease in CHOL in fish treated with 0.5% and 1% w/w F1-BEO (p < 0.05). The statistically non-significant increase in GOT and GPT in the fish fed with F1-BEO up to 3% w/w indicated a positive effect of basil on liver health. Our findings suggest a potential use for basil extracts (for example., F1-BEO) in fish feed to reduce antibiotic use and improve fish welfare.
      Citation: Fishes
      PubDate: 2022-04-13
      DOI: 10.3390/fishes7020089
      Issue No: Vol. 7, No. 2 (2022)
       
  • Fishes, Vol. 7, Pages 90: Earlier Activation of Interferon and
           Pro-Inflammatory Response Is Beneficial to Largemouth Bass (Micropterus
           salmoides) against Rhabdovirus Infection

    • Authors: Runzhen He, Qianrong Liang, Ningyu Zhu, Xiaoye Zheng, Xiaoming Chen, Fan Zhou, Xueyan Ding
      First page: 90
      Abstract: In order to understand the immune response of largemouth bass against Micropterus salmoides Rhabdovirus (MSRV), assisting disease resistance breeding, three largemouth bass breeding varieties Micropterus salmoides “Youlu No 3” (U3), “Youlu No 1” (U1) and “Zhelu No 1” (P1) were challenged intraperitoneally with MSRV. Serum and tissues were sampled to study the changes in non-specific immune parameters, viral loads, and transcript levels of immune-related genes, and the cumulative mortality rate was recorded daily for 14 days. The results showed that the cumulative mortality rates in the U1, P1, and U3 groups were 6.66% ± 2.89%, 3.33% ± 2.89%, and 0, respectively. The higher mortality may attribute to the increased viral loads after infection in the liver (2.79 × 105 and 2.38 × 105 vs. 1.3 × 104 copies/mg), spleen (2.14 × 105 and 9.40 × 104 vs. 4.21 × 103 copies/mg), and kidney (3.59 × 104 and 8.40 × 103 vs. 2.42 × 103 copies/mg) in the U1 and P1 groups compared to the U3 group. The serum non-specific immune parameters (lysozyme, catalase, and acid phosphatase) were found to be increased significantly in the U3 group. In addition, the transcripts of interferon-related genes (IFN-γ, IRF3, and IRF7) and pro-inflammatory-related genes (TNF-α and IL-1β) exhibited up-regulation and peaked at 6 h post infection in the U3 group, which also exhibited up-regulation but peaked at 12–24 h post infection in the U1 and P1 groups. In conclusion, these findings indicate that earlier activation of interferon and pro-inflammatory response is beneficial to largemouth bass against MSRV infection. This experiment may provide an insight into understanding the immune mechanism of largemouth bass against MSRV infection and contributes to molecular-assisted selection.
      Citation: Fishes
      PubDate: 2022-04-14
      DOI: 10.3390/fishes7020090
      Issue No: Vol. 7, No. 2 (2022)
       
  • Fishes, Vol. 7, Pages 91: Fluctuating Asymmetry in Asteriscii Otoliths of
           Common Carp (Cyprinus carpio) Collected from Three Localities in Iraqi
           Rivers Linked to Environmental Factors

    • Authors: Laith Jawad, Kélig Mahé
      First page: 91
      Abstract: Otoliths, calcified structures in the inner ears, are used to estimate fish age, and their shape is an efficient fish stock identification tool. Otoliths are thus very important for the management and assessment of commercial stocks. However, most studies have used left or right otoliths, chosen arbitrarily without evaluation of the difference between these otoliths. In this study, the asteriscii otoliths from 263 common carp (Cyprinus carpio; Linnaeus, 1758) were sampled in three Iraqi rivers to test the potential asymmetry and the geographical effect on otolith growth from three measurements (length, width and weight), and on shape from two shape indices (ellipticity and form-factor). Among all asteriscii otolith features, there was significant fluctuating asymmetry between fish length and every otolith descriptor. At one fish length, the size and/or the shape of otoliths could be different between two individuals and/or between left and right asteriscii otoliths for the same individual. Moreover, the relationship between fish length and otolith shape/growth was significantly dependent on the studied geographical area and, more especially, the environmental effects as the water temperature and pH. Finally, the relationships between fish length and otolith shape indices showed that the otolith evolves into the elliptical shape during the life of the fish. To use the otolith shape, it is essential to take into account the developmental stage of individuals to integrate the ontogenetic effect. Our results highlight the importance of verifying potential otolith asymmetry, especially for the asteriscii otoliths (lagenar otoliths) before their use in fisheries research.
      Citation: Fishes
      PubDate: 2022-04-15
      DOI: 10.3390/fishes7020091
      Issue No: Vol. 7, No. 2 (2022)
       
  • Fishes, Vol. 7, Pages 92: Length-Weight Relationships of 52 Species from
           the South of Sicily (Central Mediterranean Sea)

    • Authors: Fabio Falsone, Michele Luca Geraci, Danilo Scannella, Vita Gancitano, Federico Di Maio, Giacomo Sardo, Federico Quattrocchi, Sergio Vitale
      First page: 92
      Abstract: The Length-Weight relationships (LWRs) of 52 species (14 never reported before) of fishes, crustaceans and cephalopods living on the shelf and upper slope off Southern Sicily are provided. Data were collected in the framework of the International bottom trawl survey in the Mediterranean (MEDITS) in the South of Sicily (Central Mediterranean), covering a time frame ranging from 2012 to 2019. Linear regressions were significant for all species (p < 0.05) with R2 values ranging from 0.86 to 0.99. The intercept (a) of LWRs ranged from 0.0003 to 0.4677, while the slope (b) ranged from 2.1281 to 3.306. The Welch t-test, used to evaluate differences between the obtained LWRs with those reported in the literature, revealed that most of the LWRs (about 55%) reported in this study are in disagreement with those obtained previously by other authors from the Strait of Sicily. It is expected that the results obtained from this study will contribute to filling the knowledge gap of fish populations in this area and also assist fisheries scientists in future stock assessment studies.
      Citation: Fishes
      PubDate: 2022-04-17
      DOI: 10.3390/fishes7020092
      Issue No: Vol. 7, No. 2 (2022)
       
 
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